GIFT  or 

H.  E.  VAN  NORLIAN 


H.  E.  VAN  NORMAN 

6TATB  COLLEGB,  PA. 


Digitized  by  tine  Internet  Arciiive 

in  2007  witin  funding  from 

IVIicrosoft  Corporation 


http://www.archive.org/details/dairylaboratorygOOmeliricli 


DAIRY 
LABORATORY  GUIDE 


BY 


CHARLES    W.  MELICK,  B.S.A.,  M.S. 

Professor  of  Dairy  Husbandry.  Maryland  Agricultural  Experiment  Station 


FIFTT-TWO    ILLUSTRATIONS 


NEW    YORK 

D.    VAN    NOSTRAND    COMPANY 

23  Murray  and  27  Warren  Streets 

1907 

UNIVERSITY  OF  CAUFORNIA 
I  IDD  ADV 


Copyright,  1907 
By  D.  Van  Nostrand  Company 


The  Plimpton  Press  Norwood  Mass.  USA. 


CONTENTS 


EXERCISE 
I 

II 
III 

IV 

V 

VI 

VII 

VIII 

IX 

X 

XI 

XII 

XIII 

XIV 

XV 

XVI 

XVII 

XVIII 

XIX 

XX 

XXI 

XXII 

XXIII 

XXIV 

XXV 
XXVI 

XXVII 


PAGE 

Cleaning  and  Arranging  Laboratory  Ap- 
paratus Prepartory  for  use   ....  1 

Cream  Separators 2 

Separation  of  Cream 6 

The  Use  of  the  Babcock  Tester  ....  9 

The  Use  of  the  Lactometer    .      .      .      .      .  18 

Testing  the  Acidity  of  Milk 20 

Pasteurization    ........  24 

Starter  Making 28 

Curd  Test 32 

Cream  Ripening 33 

Cream  Grading 36 

Churning 38 

Determination  of  the  water  Content  of 

Butter 49 

Determination  of  Casein,  Ash,  and  Salt  of 

Butter 57 

Cheese  Making 61 

GouDA  Cheese 72 

Cottage  Cheese         72 

Ice  Cream 75 

Dairy  Bacteriology 79 

Milk  Paint 89 

Tests  for  Preservatives 90 

Test  for  Oleomargarine 91 

Repairing  Creamery  Machinery   ....  92 
Modification  of  Milk  for  Infants  and  In- 
valids       95 

Standardization  of  Milk         97 

Condensing  Milk,  Milk  Paste,  Dried  Milk, 

Milk  Sugar 100-102 

Junket,  Papanized  Cheese  Paste     .      .  102,  103 
iii 


CONTENTS 


EXERCISE 

XXVIII 


XXIX 
XXX 


XXXI 

XXXII 

XXXIII 

XXXIV 

XXXV 


PAGE 

Atimidcaseose,  Milk  Shake,  Buttermilk 
Highball,  Buttermilk  Pop,  Koumiss,  But- 
termilk, Moose,  Dried  Milk  Cocktail  104-107 
Preparations  made  from  Milk  ....  107 
Solid  Milk,  Soap,  Preparation  for  Ivy 
Poison,  A  Method  of  Modifying  Milk  for 
Invalids,  Preserving  Casein      .     .      .  108,  109 

Disinfectants 109 

Mechanical  Refrigeration 110 

Creamery  Bookkeeping 117 

Writing  to  Patrons      .         121 

Creamery  Conveniences 122 


DAIRY   LABORATORY  GUIDE 


INTRODUCTION 

This  laboratory  manual  is  published  for  the  benefit 
of  the  dairy  short  courses  where  the  classes  are  largely 
made  up  of  farm-boys  whose  education  ranges  from 
the  Eighth  Grade  to  High  School  graduates.  Con- 
sequently it  begins  with  the  most  elementary  work 
and  touches  only  the  practical  side,  with  which  every 
dairy  or  creamery  operator  should  be  familiar. 

Dairy  classes  are  usually  large,  and  where  the  in- 
structor cannot  give  personal  attention  some  students 
will  not  grasp  the  fundamental  principles  underlying 
the  work.  By  following  the  outline  of  the  manual 
the  student  may  work  out  for  himself  these  principles 
and  their  application.  There  is  also  a  growing  de- 
mand for  systematic  laboratory  work  in  the  short 
courses  where  a  large  amount  of  work  is  crowded 
haphazard  into  a  small  space  of  time.  The  purpose 
of  this  manual,  therefore,  is  to  aid  the  beginner  in 
obtaining  the  greatest  amount  of  benefit  from  the 
limited  time  spent  in  the  dairy  short  courses. 

Exercises  in  the  operation  of  boilers  and  engines 
are  not  included  in  this  manual  because  that  work 
should  be  taken  up  in  the  mechanic  arts  department. 


EXERCISE  I 


Arranging  Laboratory  Apparatus  Preparatory 

FOR  Use 

Mix  potassium  bichromate  KgCraO^  and  sulphuric 
acid  H2SO4  in  equal  parts  in  eight  to  twelve  of 
water  for  a  cleaning  mixture.  Clean  all  glassware 
with  this  mixture  by  allowing  the  articles  to  stand 


Fig.  1.  — -  l:}ottl(>  washing  machine  and  sanitary  wash  tank, 
showing  trap  connections.  This  prevents  water  from 
splashing  on  the  floor  and  soiling  clothes  or  disfiguring 
machinery.  The  horizontal  pipe  should  be  six  inches  lower 
for  convenience  in  stepping  over  it. 

submerged  in  it  for  at  least  twenty  minutes.  Re- 
move them  from  the  cleaning  mixture,  wash  with 
a  solution  of  warm  water  and  good  washing  powder, 

1 


2  DAIRY  LABORATORY  GUIDE 

rinse  thoroughly  with  hot  water  and  allow  them  to 
drain.  Wipe  every  part  of  the  remaining  labora- 
tory apparatus  with  clean  waste,  also  the  shelves 


Fig.  2.  —  Bottle  Washer 

and  drawers  to  be  used,  removing  every  particle  of 
dust.  Arrange  apparatus  in  a  neat,  convenient,  and 
orderly  manner  for  future  use. 

EXERCISE  II 

Cream  Separators 

Carefully  examine  all  parts  of  each  separator,  be- 
ginning with  the  frame.  See  that  it  is  perfectly 
level.  Why?  Note  foundation  of  the  separator  and 
see  that  it  is  solid  and  that  the  separator  is  firmly 
fastened  to  it.  Take  out  upper  and  lower  bearings 
and  wipe  carefully  with  clean  waste,  oil  with  clear 
separator  oil  and  replace.  Determine  method  of 
raising  and  lowering  the  bowl  for  proper  adjustment. 


CREAM  SEPARATORS 


Examine  parts  of  bowl  and  put  them  together. 
Place  bowl  in  the  machine  and  adjust  cream  screw. 
Turn  screw  in  to  skim  thick  cream,  and  out  to  skim 


Fig.  3.  —  Empire  Cream  Sep- 
arator showing  Bearings 

thin  cream.  Why?  Put  on  cream  and  milk  covers 
and  note  purpose  of  float.  Adjust  oil  cups  and  fill 
with  proper  separator  oil.  Find  speed  of  bowl  by 
counting  number  of  revolutions  of  bowl  to  one  of 
the  crank.     If  the  crank  makes  fifty  (50)  revolutions 


DAIRY  LABORATORY  GUIDE 


per  minute  and  the  bowl  makes  one  hundred  and 
fifty  (150)  revolutions  to  one  of  the  crank  the  speed 
of    the    bowl    is    50  X  150  =  7500    revolutions    per 


minute.  Wash  with  warm  water,  using  good  wash- 
ing powder,  rinse  with  hot  water  and  sterilize  by 
use  of  steam  or  boiling  water  all  parts  of  the  separator 
and  put  them  away,  arranging  each  so  that  no  two 


CREAM  SEPARATORS 


Fig.  5.  —  Dairy-room,  Maryland  Agricultural  Experiment 
Station,  Dairy  Building;  showing  correct  method  of 
draining  paih  and  cans;  properly  rounded  cement  cor- 
ners of  room ;  and  student  regulating  the  flow  of  oil  into 
the  upper  bearing  of  cream  separator. 

parts  touch;  they  will  thus  areate  and  dry  without 
rusting.  Repeat,  using  each  separator,  and  note 
difference  in  construction. 


Fig.  6.  —  Showing  Cases  for  separator  parts.  These  are  con- 
veniently arranged  on  the  wall  of  the  separator  room. 
The  dust  is  excluded  by  means  of  glass  doors.  Kansas 
Agricultural  College  Creamery  Building. 


DAIRY  LABORATORY  GUIDE 


EXERCISE  III 

Take  a  given  number  of  pounds  of  milk,  separate, 
and  fill  out  the  following  blank : 


SEPARATING  REPORT 
Date 


190. 


Name  of  separator  used 

Size  of  separator  used    

Rated  capacity Per  hour. 

Actual  capacity Per  hour. 

Quantity    of    milk    separated Pounds. 

Average  temperature  of  milk  entering  heater 

Average  temperature  of  milk  entering  separator 

Average  temperature  of  cream  leaving  separator 

Average  temperature  of  cream  leaving  cooler 

Average  temperature  of  skim-milk  leaving  separator 

Average  temperature  of  skim-milk  leaving  pasteurizer 

Speed  of  separator  bowl :  Listed ;  Actual 

Average  test  skim-milk    

Average  test  cream 


SEPARATOR  TEST 
Sample  Taken  from  Entire  Run 


Time  sample  taken 

Temperature  whole  milk . 
Temperature  skim-milk  . 
Temperature  cream    .  .  .  . 

Capacity  per  hour 

Speed  of  bowl    

Remarks : 


Samples 


12      3      4      5      6 


Average 


(Signed)    

O.  K Instructor. 


CREAM  SEPARATORS  7 

In  starting  the  separator  fill  the  bowl  full  of  luke- 
warm water  or  skim-milk.  Why?  Start  separator 
slowly  and  increase  to  proper  speed  in  about  three  to 
five  minutes.     Why? 

All  cream  and  skim-milk  should  be  cooled  imme- 
diately after  separating. 


Fig.  7.  —  Star  Milk  Cooler 

1.  Separate  10  gallons  of  about  4  per  cent  milk 
at  90°  F.  and  another  can  of  the  same  per  cent  milk 
at  70°  F.  Note  difference  in  test  of  cream  and  skim- 
milk. 

2.  Repeat  experiment,  using  in  one  instance  no 
flush  water  and  in  the  next  the  usual  amount;  just 
enough  to  rinse  out  of  the  bowl  the  milk  that  remains 
after  separating. 

3.  Repeat  experiment  with  separator  running  in 
perfect  condition,  and  again  with  the  bowl  unsteady 
and  vibrating. 


8 


DAIRY  LABORATORY  GUIDE 


4.  Repeat  experiment  one,  using  a  high  speed 
of  bowl  in  one  instance  and  in  the  other  a  low 
speed. 


Fig.  8.  —  Milk  Can  Washer 

5.   Similarly  separate  a  can  of  milk,  allowing  the 
milk  to  flow  slowly  through   the  separator   bowl  at 
about  one-half  capacity.     Then  separate 
can  of  milk  running  at  full  capacity. 

6.  Separate  a  can  of  milk  testing  less 
than  .2  per  cent  acid  and  another  can  at 
the  same  temperature  but  testing  35  per 
cent  to  .4  per  cent  acid.  In  every  ex- 
periment make  careful  tests  of  cream 
and  milk  to  ascertain  causes  of  varia- 
,E?,^'r,^: "~     tion  in   the  test  of  both  skim-milk  and 

Milk  Stirrer 

and  Aerator    cream. 


THE   USE  OF   THE  BABCOCK   TESTER  9 

Repeat  operation,  using  each  separator  in  dairy 
room  and  note  difference  in  skimming,  simplicity, 
and  ease  of  running.  Cool  cream  immediately  after 
separating. 

EXERCISE  IV 

The  Use  of  The  Babcock  Tester 

Examine  the  tester  and  bottles  carefully.  Note 
that  the  principle  of  centrifugal  force  in  tester  is 
same  as  that  of  the  separator.     Mix  thoroughly  a 


Fig.  10.  —  Babcock  Tester 

sample  of  whole  milk  of  about  60°  F.  by  pouring 
from  one  vessel  to  another  several  times,  so  as  to 
obtain  an  aliquot  part  of  the  mixture.  Draw  a 
sample  of  this  milk  into  a  17.6  c.c.  pipette  by  placing 
the  mouth  over  the  upper  end  and  sucking  the  air 
out  of  the  tube.  When  the  milk  rises  above  the 
17.6  c.c.  mark  remove  the  lips  from  the  tube  and 
place  the  index  finger  over  the  end  of  the  same. 


10 


DAIRY  LABORATORY  GUIDE 


Allow  the  milk  to  drop  from  the  opposite  end  of  the 
pipette  by  loosening  the  finger  slightly  until  the  edge 
of  the  meniscus  (rim  of  the  crescent  surface)  touches 


=  50 

40 


|20 

|lO 
1-0 


Fig. 


11.  — Whole  Milk 
Test  Bottle 


Fig.  12.—  Cream 
Test  Bottle 


the  17.6  c.c.  mark.  Then  place  the  contents  of  the 
tube  into  a  whole  milk  test  bottle,  adding  17.5  c.c. 
of  commercial  sulphuric  acid  from  a  graduated  bottle 


Fig.  13.  — Rack  for  Babcock  Test  Bottles 

Note.  —  For  cleaning  discolored  test  bottles  add  1  lb. 
good  washing  powder  to  a  gallon  warm  water.  Fill 
bottles  one-third  full  and  add  1  c.c.  sulphuric  acid 
to  each. 


THE   USE  OF   THE  BABCOCK   TESTER 


11 


or  cylinder,  being  careful  to  pour  the  acid  at  an  angle 
of  about  45  degrees  down  the  neck  of  the  bottle  so 
that  it  will  not  cause  a  violent  reaction  until  ready 
to  be  shaken.     Revolve  milk  and  acid  with  a  gentle 


14.  —  Pipettes 


rotary  motion  until  the  curd  of  the  milk  is  entirely 
dissolved.  Place  bottles  in  tester,  being  careful  to 
put  the  same  number  on  opposite  sides  of  the  tester 


12 


DAIRY  LABORATORY  GUIDE 


to  balance  the  machine.  Oil  tester  and  see  that  it 
runs  steadily.  Revolve  at  hsted  speed  for  three 
minutes.  Then  fill  to  the  lower  part  of  the  neck 
with  hot  water  150°  to  200°  F.  Whirl  again  for  two 
minutes  and  fill  to  the  upper  part  of  the  graduated 
neck.    Then  whirl  for  one  minute  to  a  minute  and 


Fig.  15.  —  Combined  Acid 
Bottle  and  Pipette 


a  half,  and  read  result  at  once  before  fat  column 
begins  to  cool  and  shrink.  Read  the  per  cent  of  fat 
at  about  120°  F.  If  warmer  it  will  be  too  high;  if 
colder  too  low.     Butter  fat  soUdifies  at  80°  F. 

The  speed  of  the  tester  required  to  produce  the 
necessary  centrifugal  force  depends  upon  the  diameter 
of  the  wheel  containing  the  cups.  The  less  the  diam- 
eter the  greater  the  number  of  revolutions. 


THE    USE  OF   THE  BABCOCK   TESTER 


13 


Diameter  of  Wheel  in  Inches 

Revolutions  of  Wheel  Per  Minute 

10 

1074 

12 

980 

14 

909 

16 

840 

18 

800 

20 

759 

22 

724 

24 

693 

In  reading  the  per  cent  of  fat  place  the  lower  point 
of  the  dividers  at  the  lower  surface  of  the  fat  column, 
and  the  upper  point  at  the  upper  edge  of  the  meniscus. 


16.  —  Correct  method  of  holding  dividers 
in  reading  of  the  per  cent  of  butter  fat. 
Resting  the  lower  point  of  the  dividers 
on  the  tip  of  the  thumb  facilitates  steadi- 
ness. Balance  scales  for  weighing  cream. 
Tin  box  for  washing  test  bottles. 

Now  placing  the  lower  point  of  the  dividers  at  the 
zero  mark,  and  reading  the  result  at  the  upper  point. 


14 


DAIRY  LABORATORY  GUIDE 


THE  USE  OF  THE  BABCOCK  TESTER 


15 


This  measurement  gives  a  correct  reading  for  whole 
milk.  For  cream,  take  reading  from  the  center  of 
the  meniscus,  on  account  of  the  larger  amount  of  fat 
in  neck  of  cream  bottle,  and  consequently  in  the 


meniscus. 


? 


Fig.  18.  — Scovell 
Milk  Sampling  Tube 


Fig.  19.— McKay 
Milk  Sampler 


In  testing  skim-milk  an  increased  proportion  of 
sulphuric  acid  must  be  used  on  account  of  the  lesser 
amount  of  fat  present  and  the  increased  proportions 
of  solids  which  must  be  dissolved  by  the  acid.     The 


16  DAIRY  LABORATORY  GUIDE 

reverse  is  true  of  cream.  Repeat  tests,  using  cream, 
but  instead  of  measuring  with  pipette,  weigh  on 
cream  scales  prepared  for  the  purpose,  using  18  grams 
on  account  of  the  difference  in  specific  gravity  (com- 
parative weight)  between  milk  and  cream.  A  still 
more  accurate  test  for  heavy  cream  is  obtained  by 
using  9  grams  of  cream  with  about  the  same  quantity 
of  water  and  multiplying  the  result  by  two  (2). 
The  richer  the  cream  the  more  fat  it  contains  and 
consequently  the  Hghter  it  is,  and  vice  versa. 

The  variation  between  measurements  and  weights 
of  a  given  amount  of  cream  is  as  follows: 

Cream  testing  15  per  cent  equals  8  pounds  and  7 
ounces  per  gallon. 

Cream  testing  20  per  cent  equals  8  pounds  and  6 J 
ounces  per  gallon. 

Cream  testing  25  per  cent  equals  8  pounds  and  6 
ounces  per  gallon. 

Cream  testing  30  per  cent  equals  8  pounds  and  5J 
ounces  per  gallon. 

Cream  testing  35  per  cent  equals  8  pounds  and  3 
ounces  per  gallon. 

Cream  testing  40  per  cent  equals  8  pounds  and  1 
ounce  per  gallon. 

Cream  testing  45  per  cent  equals  7  pounds  and  15 
ounces  per  gallon. 

Cream  testing  50  per  cent  equals  7  pounds  and  14  J 
ounces  per  gallon. 

Repeat;  using  in  first  experiment  less  acid;  second 
experiment,  cold  milk;  and  third  experiment,  cold 
water.     Note    results.     Similarly    test    butter    and 


THE   USE  OF   THE  BABCOCK   TESTER  17 

finely  pulverized  cheese,  using  9  grams  in  each  test, 
and  multiplying  the  result  by  2.  Obtain  accurate 
sample  by  inserting  trier  in  various  places  in  the 
cheese  or  butter  to  be  tested. 

Also  test  samples  of  ice  cream  using  a  mixture  of 
equal  parts  of  Cone,  hydrochloric  acid  and  glacial 
acetic  acid. 

Hydrochloric  acid  alone  chars  the  milk  sugar  on 
heating  almost  as  bad  as  sulphuric  acid,  and,  there- 
fore, is  useless.  Acetic  acid  alone  will  not  dissolve 
the  milk  solids,  but  the  mixture  works  perfectly. 

When  milk  has  become  sour  the  casein  may  be 
redissolved  by  adding  powdered  potash,  baking  soda, 
or  liquid  ammonia.  Care  should  be  taken  not  to 
use  too  much  alkali  as  it  reacts  with  the  acid  and 
sometimes  throws  a  part  of  the  sample  out  of  the 
bottle.  Dissolve  the  potash  or  soda  in  water  before 
using.  A  volume  equal  to  about  5  per  cent  of  the 
volume  of  the  milk  will  be  sufficient  to  dissolve  the 
casein.  This  solution  increases  the  volume  of  milk 
and  thus  necessarily  decreases  the  per  cent  of  fat. 
Measure  the  volume  of  milk  to  be  tested,  and  meas- 
ure the  solvent  before  adding.  Calculate  the  de- 
crease in  the  per  cent  of  fat  in  the  following  manner : 

If  9  cubic  centimeters  of  alkaline  solution  has  been 
added  to  180  cubic  centimeters  milk  to  dissolve  the 
casein,  which  is  5  per  cent  of  the  milk  used  (180: 9  : 
:100:x=5),  the  mixture  gives  a  test  of  3.9  per 
cent  of  butter  fat.  The  test  must  be  increased  0.195 
per  cent  (3.9  X  .05  =  0.195).  Hence,  the  per  cent  of 
fat  in  the  original  milk  is  4.095  (3.9  +  0.195  =  4.095). 


18  DAIRY  LABORATORY  GUIDE 

Testing  Strength  of  Acid 

Test  strength  of  acid  by  finding  its  specific  gravity, 
which  should  be  1.82  to  1.83.  This  can  be  done  by 
weighing  an  exact  measured  volume  of  acid  and 
comparing  its  weight  with  the  same  volume  of 
distilled  water.  Then  divide  the  weight  of  the  acid 
by  the  weight  of  the  same  volume  of  water  and  the 
quotient  will  be  the  specific  gravity  of  the  acid.  If 
the  fat  column  is  very  light  and  contains  white 
specks  the  acid  is  too  weak,  not  enough  used,  or 
milk  was  too  cold.  If  very  dark  or  if  it  contains 
black  specks  the  acid  is  too  strong,  too  much  was 
used,  or  milk  or  acid  was  too  hot.  The  fat  column 
should  be  of  a  light  straw  color. 

EXERCISE  V 

Use  of  the  Lactometer 

The  lactometer  is  used  to  determine  the  specific 
gravity  of  a  Uquid;  that  is,  its  weight  compared  with 
the  weight  of  an  equal  volume  of  distilled  water. 
Where  a  given  volume  of  distilled  water  weighs  one 
pound,  an  equal  volume  of  whole  milk  weighs  1.029  to 
1.033,  depending  upon  the  per  cent  and  kind  of  solids 
present.  The  higher  the  per  cent  of  fat  in  milk  the  less 
the  specific  gravity  and  vice  versa.  The  specific  grav- 
ity of  milk  serum  is  1.036.  That  of  fat  is  .93.  The 
Quevenne  lactometer  is  generally  used.  Examine  the 
lactometer  carefully  and  note  enclosed  thermometer 
and  graduations.     Place  in  graduated  beaker  of  milk 


USE  OF   THE  LACTOMETER 


19 


having  a  temperature  of  50°  F.  Heat  milk  to  60°  F., 
noting  changes  in  lactometer  reading.  Take  sample 
of  milk  for  fat  test  and  set  it  aside.     Now  add  a 


20.  —  Quevenne  Lactometers 


definite  proportion  of  water  to  the  milk  in  the  beaker 
and  take  readings  at  the  same  temperatures  as  before. 
What  is  the  difference?    ^Vhy?    Calculate  formula 


20  DAIRY  LABORATORY  GUIDE 

for  obtaining  correct  readings  at  varying  tempera- 
tures. Find  solids  not  fat,  and  per  cent  of  water  as 
follows :  i  of  fat  found  in.  the  milk  plus  I  of  lactometer 
reading  equals  solids  not  fat.  Total  solids  are  ob- 
tained by  adding  the  solids  not  fat  to  the  fat.  For 
example:  Where  lactometer  reading  is  32  and  fat  is 

3.5  per  cent  (^^  +  ^)  =  (8.0  +  .7)  =  8.7;  8.7  + 

3.5  =  12.3  =  total  solids.  For  finding  per  cent  of 
water  in  milk:  solids  not  fat  of  normal  milk  minus 
solids  not  fat  in  watered  milk,  multiplied  by  100 
and  divided  by  solids  not  fat  of  normal  milk,  equals 
per  cent  of  adulteration.     For  example: 

S.  N.  F.  Normal  Milk  -  S.  N.  F.  Adulterated  Milk 
S.  N.  F.  Normal  Milk 

X  100  =  per  cent  adulteration. 

EXERCISE  VI 

Testing  Acidity  of  Milk 

The  acidity  of  normal  milk  is  caused  by  the  breaking 
down  of  milk  sugar  by  bacteria  and  converting  it 
into  lactic  acid.  The  change  is  supposed  to  occur 
in  the  following  manner : 

Milk-sugar.        Water.         Lactic  acid. 

C12H22OU  +H2O  =4C3H603 

There  are  several  tests  for  the  acidity  of  milk. 
Those  most  commonly  used  are  as  follows: 
Mann's  Acid  Test. 
Farrington's  Alkaline  Test, 


TESTING  ACIDITY  OF  MILK 


21 


Van  Norman's  Alkaline  Test. 
Marshall's  Acid  Test. 

Mann's  Acid   Test 

Fill  a  50  c.c.  burette  to  zero  mark  with  tenth 
normal  solution  of  sodium  hydroxide  NaOH.  Meas- 
ure 50  c.c.  of  milk  or  cream  to  be  tested  into  a 
beaker.  In  the  case  of  cream  dilute  with  water, 
the  amount  depending  upon  the  thickness  of  the 
cream.  Add  a  few  drops,  tw^o 
to  five,  of  indicator;  phenolph- 
thalein  is  generally  used.  Add 
the  alkali  solution  to  the  cream 
very  slowly,  and  stir  constantly 
until  a  permanent  pinkish  color 
remains  in  the  milk.  The  per 
cent  of  acid  is  found  by  mul- 
tiplying the  number  of  c.c.  of 
alkali  solution  used  by  .009, 
dividing  by  the  number  of  c.c. 
of  milk  or  cream  used  and  mul- 
tiplying the  result  by  100.  The 
explanation  of  this  formula  is 
that  the  alkali  of  the  sodium 
hydroxide  neutrahzes  the  acid  Fig.  21.  —  Acid  Bottle 
of  the  milk.     1  c.c.  of  tenth  nor-  ^^ 

mal  solution  contains  .004  of  a  gram  of  sodium  hy- 
droxide which  neutralizes  .009  of  a  gram  of  lactic 
acid.  This  is  obtained  from  the  fact  that  a  normal 
solution  of  lactic  acid  contains  90  grams  of  acid  in 
each  hter,  or  1000  c.c.     Example: 


22  DAIRY  LABORATORY  GUIDE 

c.c.  alkali  34  X  .009     ^.^^       .^^^      ., 
50  c.c.  Cream  X 1  00  =  .612%  acid. 

Obtain  by  means  of  a  pipette  a  sample  of  milk 
from  the  top  and  one  from  the  bottom  of  a  beaker 
of  milk  that  has  been  allowed  to  stand  for  several 
minutes.    Test  and  note  difference.     AVhy? 

Farrington^s  Alkaline  Test 

Dissolve  five  of  Farrington's  tablets  in  enough 
water  to  make  solution  97  c.c.  Mix  well  and  measure 
out  17.6  c.c.  of  the  milk  or  cream  to  be  tested,  and 
add  the  alkali  solution  as  in  previous  tests  until  the 
characteristic  pink  color  remains.  The  number  of 
c.c.  of  alkali  solution  required  to  produce  this  result 
indicates  the  number  of  hundredths  per  cent  acid, 
since  1  c.c.  of  alkali  neutraUzes  .01  per  cent  of  acid 
when  17.6  c.c.  of  milk  are  used.  Therefore  the 
number  of  c.c.  neutralizer  used  divided  by  100 
equals  per  cent  of  acid.  For  instance:  If  50  c.c. 
solution  be  used  the  acidity  of  the  milk  in  question 
is  .5  per  cent.  The  Farrington  tablets  contain  alkali 
equal  to  3.8  c.c.  of  tenth  normal  solution  and  also 
the  color  indicator. 

Van  Norman's  Alkaline  Test 

Pour  into  a  1000  c.c.  graduated  flask  20  c.c.  of 
normal  caustic  soda  (NaOH)  solution,  fill  to  the 
1000  c.c.  mark  with  distilled  water,  making  50th 
normal  alkah  solution.  Put  17.6  c.c.  bf  milk  or 
cream  to  be  tested  into  a  beaker  and  add  four  to 


TESTING  ACIDITY  OF  MILK  23 

five  drops  of  phenolphthalein.^  Allow  the  alkali  solu- 
tion to  drop  slowly  into  the  milk  or  cream  being 
tested;  meanwhile  continually  stir  until  a  pinkish 
color  is  noticeable  which  does  not  disappear  imme- 
diaetly  by  continued  stirring.  The  number  of  c.c. 
of  alkali  solution  required  to  bring  about  this  result 
will  indicate  the  number  of  hundredths  per  cent  of 
acid,  since  1  c.c.  of  alkali  will  neutralize  .01  per 
cent  of  acid  when  17.6  c.c.  of  milk  or  cream  is  used, 
as  in  Farrington's  Test.  Thus  if  50  c.c.  neutralizer 
be  used  the  milk  has  an  acidity  of  .5  per  cent. 

MarshalVs  Acid  Test 

Carefully  mix  milk  or  cream  to  obtain  an  accurate 
sample  as  in  above  cases,  and  fill  a  9  c.c.  pipette  with 
one-tenth  normal  solution  alkali  as  prepared  at  the 
factory.  Add  from  two  to  four  drops  of  indicator. 
Allow  alkali  solution  to  drop  into  the  milk,  constantly 

»  Phenolphthalein  is  one  of  the  dyes  made  by  a  combination 
of  certain  coal  tar  derivatives  (phenols)  with  phthalic  acid;  in 
the  presence  of  free  alkali  a  chemical  combination  is  formed 
having  a  red  color.  When  a  few  drops  of  phenolphthalein 
solution  are  added  to  milk  containing  free  lactic  acid  no  color 
is  appreciable  in  the  milk;  as  the  alkali  is  added  the  lactic  acid 
(which  has  a  greater  afhnity  for  the  alkali  than  has  the  phenol- 
phthalein) is  neutralized;  and  as  soon  as  it  is  all  neutralized  the 
slightest  further  addition  of  alkali  changes  the  indicator  to  a 
pink  color.  Shaking,  or  stirring,  during  the  test  is  necessary 
because  the  effect  of  the  alkali  in  producing  the  red  or  pink 
color  in  the  indicator  may  be  seen  locally,  where  the  alkali  falls 
into  the  milk,  before  the  acid  in  the  milk  is  all  neutralized.  As 
soon  as  all  the  acid  in  the  sample  is  neutralized  the  pink  color 


24 


DAIRY  LABORATORY  GUIDE 


stirring  as  in  the  previous  tests  until  a  permanent 
pink  color  remains  in  the  milk.  The  number  of  c.c. 
used  divided  by  10  indicates  the  per  cent  of  acid  in 


Fig.  22.  —  Apparatus  for  Marshall's 
Acid  Test 

the  milk  or  cream  being  tested.  Thus,  if  two  (2)  c.c. 
of  neutralizer  has  been  used  the  milk  contains  .2 
per  cent  of  acid. 

EXERCISE  VII 

Pasteurization 

Fill  jacketed  space  of  pasteurizer  with  water  and 
turn    on    steam    until    the    desired    temperature    is 


PASTEURIZATION 


25 


reached;  from  150°  to  190°  F.,  depending  on  condi- 
tion of  milk.  Start  motion  of  pasteurizer  by  throwing 
belt  on  tight  pulley,  and  when  the  desired  speed  is 
reached  open  milk  inlet.  Notice  temperature  of  milk 
at  the  outlet  from  pasteurizer  and  regulate  by  the 
connecting  steam  valve.  Draw  pasteurized  milk  off 
into  sterile  cans,  placing  a  clean  white  cloth  or 
parchment  paper  above  spout  and  opening  of  can 
to  prevent  contamination  from  the  surrounding 
atmosphere.  Among  the  pasteurizers  in  common 
use  are  the  Jensen,  Reid,  Miller-Tyson,  Miller,  and 
Farrington. 


The  Miller-Tyson  Pasteurizer 

The  machine  is  dependent  upon  centrifugal  force 
for  its  action.  The  film  decreases  in  thickness  and 
increases  in  speed  as  it  nears  the  periphery  of  the 
treating  plate.     It  requires  fifteen  seconds  to  com- 


9 

'H^   jiiJlf'  L 

y^^Li^'.-. .      1 

■ll|dMgWin^i^^j^ 

'       1:5 

T 

Fig.  23 


26  DAIRY  LABORATORY  GUIDE 

plete  the  process  of  pasteurization,  heating  to  180 
degrees,  and  cooHng  to  desired  temperature. 

After  pasteurization  there  is  no  milk  left  in  machine 
and  it  does  not  have  to  be  taken  apart  for  cleansing, 
but  by  Ufting  covers  all  contact  surfaces  are  in  direct 
view  and  can  be  touched  with  a  brush. 

It  is  said  to  be  equally  adapted  for  the  pasteuriza- 
tion of  sweet  milk  and  thick,  sour  cream. 

The  essential  point  in  the  construction  of  a 
Regenerator  is  the  employment  of  a  non-conducting, 
revolving  cyUnder  which  permits  the  uniting  in  a 
single  apparatus,  the  heating  on  a  water-heated 
surface  with  an  effective  interchange  of  heat.  The 
Regenerator  consists  of  a  bank  of  pipes,  perfectly 
smooth  inside,  connected  by  means  of  vertical  end 
plates,  and  communicating  one  with  the  other  by 
means  of  sanitary  detachable  manifolds.  The  milk 
coming  from  the  Pasteurizer  passes  through  this 
bank  of  pipes,  entering  the  same  at  the  bottom, 
and  being  discharged  at  the  top  so  that  the  hottest 
milk  fills  the  lowest  pipe,  and  as  it  becomes  colder, 
the  coldest  milk  leaves  at  the  top  to  be  discharged 
to  the  cooler.  The  cold  milk  runs  over  this  bank 
of  pipes  on  the  outside,  striking  a  pipe  first 
nearly  its  own  temperature  and  gradually  becoming 
hotter  as  it  passes  down  over  the  apparatus,  finally 
getting  almost  as  warm  as  the  milk  lea\dng  the  Pas- 
teurizer. A  great  saving  is  therefore  effected  in  the 
use  of  steam  on  the  one  hand,  and  in  the  use  of  cool- 
ing with  cold  water  or  ice  on  the  other.  In  other 
words  the  heat  which  has  once  been  imparted  to  the 


PASTEURIZATION 


27 


milk  by  means  of  the  Pasteurizer  is  used  to  partly 
heat  the  milk  wliich  shall  enter  the  Pasteurizer,  while 
the  cold  milk  helps  to  cool  that  which  flows  from  it. 
It  is  obvious  that  if  the  service  of  conduct  is  large 
enough  a  complete  exchange  of  the  two  temperatm'es 
must  take  place. 


28  DAIRY  LABORATORY  GUIDE 

EXERCISE  VIII 
Starter  Making 

Sterilize  a  clean-flavored  batch  of  sweet  skimmed 
or  whole  milk  by  running  it  through  a  pasteurizer 
and  heating  to  about  212°  F.,  preferably  two  days  in 
succession.  Allow  the  milk  to  run  into  a  sterile 
quart  bottle.^  Cover  spout  of  pasteurizer  and  open- 
ing in  the  bottle  with  clean  white  cloth  or  parch- 
ment paper  to  prevent  contamination  from  the 
surrounding  atmosphere,  as  in  the  case  of  pasteur- 
ization. Cover  bottle  as  soon  as  full  and  cool  to 
80°  F.  Add  contents  of  bottle  or  capsule  of  com- 
mercial culture  and  allow  to  remain  at  80°  F.,  until 
milk  becomes  partially  thickened,  or  has  the  consist- 
ency of'  thick  cream.  This  usually  requires  from 
eight  to  twelve  hours.  At  this  stage  it  is  called 
startoUne.  Pour  from  the  top  of  the  bottle  into  a 
can  containing  from  five  to  ten  gallons  of  pasteur- 
ized milk  the  entire  contents  of  the  bottle,  with  the 
exception  of  about  one  tablespoonful  remaining  in 
the  old  bottle.  Put  the  spoonful  of  starter  remain- 
ing in  the  old  bottle  into  a  clean  sterile  bottle  and 

*  Where  glass  jars  are  used  a  steaming  cabinet  is  very  con- 
venient. This  should  be  made  to  hold  three  times  as  many 
jars  as  are  required  daily.  Place  one  day's  supply  in,  heat  to 
from  200°  to  212°  F.  for  half  an  hour.  On  the  following  day  add 
a  like  number  and  repeat  the  heating.  On  the  third  day  add 
another  day's  supply  and  again  repeat  the  heating.  The  first 
jars  have  now  received  three  applications  of  heat  and  are  prac- 
tically sterile.  By  replacing  each  day  as  many  jars  as  are  taken 
out  a  supply  of  sterile  mother  starter  is  constantly  on  hand. 


STARTER  MAKING 


29 


add  enough  milk  to  continue  the  propagation  of  the 
original  culture,  being  careful  thereafter  to  keep 
at   70°   F.     Stir   every   half   hour   as   before.     Mix 


OTHER  PATENTS  PENOINO 


Fig.  25.  —  Trunnioned  Starter  Can.  This  Starter  Can 
is  trunnioned  on  its  frame  in  such  a  manner  that 
the  starter  may  be  drawn  off  from  the  top,  leaving 
the  lower,  less  contaminated  portion  for  propaga- 
tion. The  agitators  serve  to  keep  the  starter  in  a 
uniform  condition  while  ripening. 

The  space  between  the  jacketed  sides  may  be  used 
for  cold  water  in  the  summer,  and  warm  water  in 
the  winter  to  maintain  an  even  temperature  about 
70°  F. 

thoroughly  the  starter  and  skim-milk  in  can  and 
allow  to  stand  at  70°  F.,  until  the  proper  consistency 
is  reached,  when  it  is  ready  for  use.  The  following 
blank  form  may  be  used  in  this  exercise : 


30  DAIRY   LABORATORY   GUIDE 

STARTER  REPORT 

Date 190 


Kind  of  starter  made  (Ericsson,  Douglas,  Hansen,  Parke  Davis, 

etc.,  or  natural) 

Number  of  culture  used 

Pounds  of  milk  used 

Acid  test  of  milk  before  heating 

Temperature  of  heating 

Time  held  at  this  temperature 

Temperature  after  cooling 

Quantity  of  culture  used 

Time  of  setting   


ACIDITY   OF  STARTER 


Time 


Temperature 


Test 


Held  at  what  temperature  when  ripe 
Describe  flavor: 


Remarks: 

(Signed)    

O.  K Instructor. 


In  preparing  starter  it  is  advisable  to  keep  several 
samples  of  mother  cultures  propagating.  If  an  incu- 
bator cannot  be  obtained  a  small  cream  vat  may  be 
converted  into  a  form  of  incubator  which  may  be 
used  for  maintaining  an  even  temperature,  where 
such  samples  or  small  quantities  of  milk  or  cream 
may  be  kept.     These  vats  are  double-lined,  having 


STARTER  MAKING 


31 


a  dead  air  space  of  about  three  inches  between  the 
tin  jacket  and  outer  tank.  This  space  surrounds  the 
entire  tin  jacket  or  inner  tank,  and  can  be  filled  with 
warm  air  in  the  winter  and  cold  in  the  summer,  to 
impart  uniform  temperature  to  the  samples  contained 
therein.    About  six  inches  of  water  may  be  kept  in 


Fig.  26 

the  tank  to  aid  in  maintaining  an  even  temperature. 
Ice  may  be  used  in  summer  if  obtainable.  Of  course 
the  opening  E  should  be  closed  in  the  summer.  The 
accompanying  cut  represents  the  vat.  E  represents 
the  opening  from  below  to  the  dead-air  space  and 
the  place  for  the  lamp  which  is  kept  burning  con- 
tinually except  when  room  temperature  is  70°  F.  or 


32  DAIRY  LABORATORY  GUIDE 

warmer.  The  lamp  keeps  the  air  warm  and  at  an 
even  temperature  regardless  of  the  weather.  In  case 
of  extreme  cold  weather  the  burner  may  be  turned 
higher  than  in  warm  weather.  D  represents  the  slats 
used  in  the  bottom  of  the  tank  which  allows  the 
water  to  come  in  contact  with  bottom  of  the  pails 
or  bottles  used. 

EXERCISE  IX 

Curd  Test 

Make  curd  tests  by  placing  in  composite  sample 
bottles,  or  other  convenient  glass  jars,  samples  of 


Fig.  27.  ■ —  Curd  of  Milk  from  Sterilized  Separator 

various  kinds  of  milk  to  be  tested.     Heat  to  90°  F. 
and  add  a  few  drops  of  rennet,  depending  upon  the 


Fig.  28.  —  Curd  of  milk  from  separator  merely  flushed 
with  warm  water.  The  milk  in  both  instances  was 
pasteurized  before  separating. 

quantity  of  milk  used.     Place  in  incubator  or  warm 
room  and  allow  to  remain  until  curdled.     Remove 


CREAM  RIPENING  33 

slices  of  curd  with  sterile  knife  and  examine  for 
flavor,  odor,  etc.  Remove  whey  and  allow  samples 
to  remain  from  eight  to  twelve  hours  and  examine  as 
before.  Also  note  presence  or  absence  of  pin-holes 
and  other  defects  caused  by  gas  forming  or  putrefac- 
tive bacteria. 

EXERCISE  X 

Cream  Ripening 

After  separating  and  pasteurizing  as  indicated  in 
Exercises  3  and  7,  add  starter  as  prepared  in  Exercise 
8,  the  amount  depending  on  the  per  cent  acid  in 
the  cream  and  the  length  of  time  previous  to  churning. 
Keep  the  cream  at  70°  F.  during  cold  weather  and 
60°  F.  in  warm  weather,  until  an  acidity  of  about 
.5  per  cent  has  developed.  Now  cool  the  cream  to 
45°  F.  and  allow  it  to  remain  at  that  temperature 
for  at  least  two  hours,  when  it  is  ready  to  churn. 
Why  leave  at  this  temperature  so  long?  Heat  to 
50°  F.  for  churning  in  summer  and  55°  F.  for  churn- 
ing in  winter. 

Formula  for  Adding  Starter  to  Siveet  Cream,  or  Cream 

which  is  to  he  churned  immediately  loithout 

ripening. 

Suppose  your  standard  of  acidity  for  ripened 
cream  is  .5  per  cent,  that  of  the  starter  is  .9  per  cent, 
and  the  standard  amount  of  starter  is  10  per  cent,  the 
acidity  of  the  cream  on  hand  is  .4  per  cent,  and  that 
of  the  starter  is  .8  per  cent;  then 


34 


DAIRY  LABORATORY  GUIDE 


.5X90  +  .9X10-.4X100 


8 -.4 


35    per  cent   starter   to 


be  used. 


a1 


a  .5 
bC   o 


<     O 

o  ^ 
Si     c3 


bC   5 


Experiment  with  the  use  of  commercial  lactic  acid 
for  ripening  cream,  using  from  10  to  20  c.c.  per  gallon. 


CREAM  RIPENING  35 

The  following  blank  form  may  be  used  in  this 
exercise : 

CREAM  RIPENING  REPORT 

Date 190 

Name  and  capacity  of  vat  used 

Pounds  of  cream  in  vat   

Pounds  of  starter  added    

Kind  of  starter  used 

Acidity  of  starter  when  used 

Number  of  culture    

Babcock  test  of  cream  after  adding  starter    

Required  acidity 

Was  cream  pasteurized?    


TESTS   FOR  ACIDITY 

Time 

Temperature 

Test 

Time  required  to  ripen 

Temperature  to  which  cream  was  cooled 

Acid  test  after  cooling 

Manner  of  cooling 

Remarks: 


(Signed)    

O.   K Instructor. 

Viscogen 

When  cream  has  been  pasteurized  above  150°  F. 
its  viscosity  is  reduced  by  a  loosening  of  the  galactase 
which  holds  the  fat  globules  in  groups.     To  restore 


36  DAIRY  LABORATORY  GUIDE 

the  viscosity  add  viscogen.  The  formula  for  vis- 
cogen  is  2 J  parts  of  sugar,  or  all  that  will  dissolve 
without  caramaUzing,  5  parts  water,  -^q  part  milk 
of  lime.  Prepare  one  gallon.  Mix  thoroughly  and 
allow  to  stand  for  at  least  twenty-four  hours.  Vis- 
cogen is  an  alkali  and  if  too  much  be  added  it  gives 
a  bad  odor  and  bitter  taste.  One  ounce  of  viscogen 
is  sufficient  to  restore  the  viscosity  in  five  gallons  of 
sweet  cream.  The  higher  the  per  cent  of  acidity  the 
more  it  will  require.  Where  viscogen  is  added  to 
cream  for  market  it  should  be  labeled  visco-cream. 

EXERCISE   XI 
Cream  Grading 

Make  acid  test;  curd  test;  heat  a  sample  of  milk  or 
cream  to  120°  F.,  and  note  odor.  Take  lactometer 
reading.  First-grade  cream  should  test  between  30 
and  50  per  cent  butter  fat,  from  0  to  .2  per  cent 
acid,  and  have  a  good  clean  flavor.  Second-grade 
cream  may  test  from  20  to  50  per  cent  butter  fat  and 
have  not  higher  than  .3  per  cent  acid,  and  fair  flavor. 
Third-grade  cream  should  not  be  used  for  butter- 
making. 

A  test  for  ammonia  in  milk  or  cream  may  also  be 
made  by  adding  10  c.c.  of  10  per  cent  solution  of 
bichloride  of  mercury  and  potassium  iodide  (Nessler's 
Reagent)  to  10  c.c.  of  milk.  A  precipitate  is  at  once 
thrown  down.  Filter  and  add  3  per  cent  solution  of 
pure  milk  of  Ume  until  a  black  precipitate  is  formed 
which  disappears  with  an  excess  of  reagent.     This 


CREAM  GRADING 


37 


test  is  seldom  used  and  is  unnecessary  except  where 
the  water  used  in  the  dairy  is  suspected  of  being  con- 
taminated with  sewage. 

Scrupulous  cleanUness  should  be  practised  in 
bottUng  milk.  It  should  never  be  retailed  in  any 
other  form.  The  caps  should  never  be  removed 
until  dehvered  to  the  consumer. 


SCORE   CARD    FOR  MILK 
Date 


Perfect 

Underscore 
Defects 
Noted 

r^            -x-       /on  rry  \  J  Per  cent  of  fat . . . . 

Composition  (30%) 

'■                     N         /^         SnliHs  nnf  fat, 

3.5  to  5  % 
8  to  10  % 

0  to  .2  % 

0 

0 

0  to  3000% 

Acid 

Keeping  Quality 
(30%) 

Dirt 

Ferments 
High    bac- 
terial con- 
tent 

Bitter 

Flat 

Clean 

Stable 

Flavor  (40  %) 

Cowv 

Tainted 

Weedy 

Total 

38  DAIRY  LABORATORY  GUIDE 

Flavor 40 

Composition 25 

Bacteria    20 

Acidity 5 

Appearance  of  package  and  contents 10 

The  score  cards  used  for  milk  and  cream  by  the 
Dairy  Division,  Washington,  D.  C: 

CREAM  SCORE  CARD 

FLAVOR  CONDITION 

Taste  Smell  Cleanliness  Acidity  Total 

30  30  20  20  100 

MILK  SCORE  CARD 

FLAVOR  *  CONDITION 

Taste    Smell  Curd  Test  Cleanliness    Acidity   Total 

25         25  25  15  10  100 

EXERCISE  XII 

Churning 

Rinse  churn  with  hot  water  from  150°  to  200°  F., 
revolving  it  from  five  to  ten  times,  being  careful  to 
leave  stopper  out.  Draw  off  water  and  rinse  again 
in  the  same  manner  with  pure  cold  water  at  about 
40°  to  50°  F.,  leaving  stopper  in  during  the  last 
rinsing.  Draw  off  water  and  pour  the  ripened  cream 
in,  filling  churn  about  one-third  full  so  as  to  allow 
the  greatest  splash  in  churning.  Add  vegetable 
coloring,  the  amount  depending  on  the  time  of  the 
year  and  the  market  requirements.  If  cows  are 
receiving  no  grass  and  the  market  demands  a  high 
color,  an  ounce  or  30  c.c.  color  to  each  50  pounds 


CHURNING 


39 


of  butter  fat  may  be  used.  Put  cover  on  tight 
and  set  churn  in  motion,  removing  stopper  two  or 
three  times  during  the  first  part  of  the  churning 
to  allow  the  moist  air  to  escape. 


°  Wff'°''^ 


7.1^ 


Fig.  30.  — Disbrow  Coinl)iiied  Churn  and  Worker  with  sections 
showing  butter  being  worked. 

When    the  butter  has  gathered    in  granules    the 
size  of  number  4  to  00  shot  stop  the  churn  and  draw 


40  DAIRY  LABORATORY  GUIDE 

off  buttermilk.     Rinse  once,  using  one-quarter  of  the 
churnful  of  sterile  water,  or  as  pure  as  can  be  ob- 


FiG.  31.  —  Churning  and  Cream  Ripening  Department  of  the 
Model  Dairy  of  the  Louisiana  Purchase  Exposition, 
showing  machinery  operated  V)y  a  5-horse-power  dy- 
namo. This  is  the  most  sanitary  source  of  power  ob- 
tainable for  a  creamery.  One  of  the  most  important 
precautions  for  the  beginner  in  the  use  of  a  dynamo  is 
that  of  starting  and  stopping.  In  starting  the  current 
is  first  connected  with  the  switch.  Then  the  crank  or 
starting  rheostat  is  moved  slowly  over  the  controlling 
box  to  the  magnet  which  holds  it  in  place,  while  the 
current  is  on.  If  the  starting  rheostat  is  moved  over 
quickly  the  field  in  the  controlHng  box  does  not  "catch 
up ' '  with  the  current  immediately  and  a  fuse  may  be 
blown  out,  or  the  field  overstrained.  In  stopping  the 
dynamo,  disconnect  current  by  merely  throwing  off 
switch.  Never  try  to  move  starting  rheostat  back  while 
current  is  on.  Use  nothing  but  insulated  copper-wire 
for  connections,  and  see  that  they  are  kept  clean  and 
tight. 

tained,  revolving  the  churn  about  three  times.  Draw 
off,  and  if  water  still  has  milky  color  rinse  again, 
otherwise  not.     Add  salt,  depending  on  the  market 


CHURNING 


41 


requirements.  One  ounce  and  a  half  of  salt  per 
pound  of  butter  fat  is  usually  sufficient.  See  that 
salt  is  kept  in  a  warm  place,  and  to  give  best  re- 
sults the  salt  must  not  be  colder  than  the  butter. 


Fig.  32 

The  condition  of  the  salt  has  a  great  effect  upon 
mottles.^    Throw  workers  into  gear,  using  low  speed. 

1  The  cause  is  the  uneven  distribution  of  salt.  If  butter  is 
churned  at  a  warm  temperature  the  outside  of  the  granules  are 
chilled  while  the  butter  on  the  inside  is  still  soft.  The  soft  butter 
on  the  inside  will  take  up  the  salt  more  easily  than  the  outside 
which  is  harder,  and  thus  produces  mottles. 

The  same  condition  is  obtained  by  having  butter  too  firm  to 
work  so  that  it  is  impossible  to  get  the  salt  mixed  thoroughly 
through  the  butter;  or  by  churning  very  cold  cream  and  using 
warm  wash  water.  Going  from  one  extreme  to  another  in  tem- 
perature is  likely  to  cause  mottles. 


42  DAIRY  LABORATORY  GUIDE 

Revolve  churn  about  ten  times  and  allow  to  stand 
for  twenty  minutes  to  give  the  salt  a  chance  to 
dissolve  evenly.  Work  ten  revolutions  more,  take 
out,  and  print  or  pack  in  cases  or  tubs  which  have 
been  previously  scalded  and  coated  on  the  inside 
with  paraffin  at  250°  to  260°  F.     Why? 

In  the  summer  give  the  Disbrow  churn  19  to  20 
revolutions.  In  the  winter  it  is  necessary  to  increase 
it  to  25  to  28  in  order  to  give  the  butter  the  same 
amount  of  working.  Where  a  Victor  churn  is  used, 
in  place  of  9  revolutions  as  in  summer,  it  will  re- 
quire 11  to  12  in  the  winter. 

Calculate  per  cent  of  overrun  as  follows: 

Pounds  of  butter  minus  pounds  of  butter  fat  equals 
number  pounds  overrun.  Number  of  pounds  of  over- 
run divided  by  pounds  of  butter  fat  equals  per  cent 
overrun;  for  example,  800  pounds  of  butter  fat  make 
900  pounds  of  butter.  900  -  800  =  100.  100  -^ 
800  =  12J  per  cent  overrun. 

The  following  blank  form  may  be  used  for  this 
exercise: 

Date 190.  .  .  . 

Pounds  butter-fat  computed  from  exercise  No.  4 

Estimated  pounds  of  butter   

Pounds  of  butter  made    

Per  cent  overrun 

Kind  and  size  of  churn  used 

Temperature  of  cream  in  vat    

Time  since  cooling    

Acid  test 


CHURNING 

4^ 

rcentage  of 

Pounds  overrun  on 

80,000 

Value  of  overrun 

overrun 

pounds  butter 

fat 

at  25c.  per  pound 

22.5 

18,000 

$4,500 

22 

17,600 

4,400 

20 

16,000 

4,000 

19 

15,200 

3,800 

18.9 

15,120 

3,780 

18.25 

14,600 

3,650 

18 

14,400 

3,600 

17.82 

14,256 

3,564 

17.8 

14,240 

3,560 

17.71 

14,168 

3,542 

16.7 

13,360 

3,340 

16 

12,800 

3,200 

15 

12,000 

3,000 

14.1 

1 1 .280 

2,820 

13 

10,400 

2,600 

12 

9,600 

2,400 

9 

7,200 

1,800 

8.94 

7,152 

1,788 

8.6 

6.880   • 

1,720 

7.5 

6,000 

1,500 

5.84 

4,672 

1,168 

In  packing  a  tub  of  butter  first  boil  the  tub  in  a 
strong  solution  of  brine  to  rid  it  of  all  undesirable 
bacteria  and  mold,  apply  melted  paraffin  on  entire 
inner  surface  and  then  set  in  the  refrigerator  to  cool 
off  while  churning.  Only  the  best  of  circles  and 
liners  should  be  used  and  these  should  be  soaked 
about  twelve  hours  in  a  cool  brine  solution  which 
has  been  previously  boiled.  After  the  butter  has 
been  properly  worked  the  brine  is  poured  from  the 
tubs,  and  the  small  circles,  still  wet,  are  placed  in  the 
bottom  of  the  tub ;  the  liner  should  then  be  put  in  wet 
and  neatly  pressed  into  place,  leaving  about  an  inch 


44  DAIRY  LABORATORY  GUIDE 

above  the  top  of  the  tub.  It  should  then  be  turned 
down  over  the  rim  of  the  tub  to  prevent  wrinkhng 
in  packing  the  butter.  All  wrinkles  or  kinks  should 
be  carefully  smoothed  out  before  putting  the  butter 
into  the  tub.  If  the  butter  is  then  put  in  in  small 
quantities  and  carefully  packed  there  will  be  no  holes. 
Do  not  pack  enough  to  spoil  the  grain.  After  packing 
the  butter  until  the  tub  is  rounding  full,  cut  the  top 
smooth  by  means  of  a  fine  wire  trimmer,  then  turn 
the  projecting  inch  of  the  hner  back  over  the  top 
surface  of  butter;  place  a  cheese-cloth  circle  over 
this  and  cover  the  latter  with  the  top  paper  circle. 
A  single  handful  of  salt  should  be  sprinkled  over  the 
paper  circle  and  the  cover  nailed  neatly  on. 

RAW   MATERIAL   SCORE 

Quality 95 

Cans    5 

Total 100 

Organization.  —  Individual,  Cooperative,  Stock  or  Centralized 

Name  of  Creamery 

Post  Office County State   


Inspector. 


CHURNING  45 


BLANK    FORM    FOR   CLASS    IN    CHURNING 

Kind  of  color  used 

Kind  of  salt  used    

C.  C.  or  ounces  color  per  100  lbs.  butter-fat Total  C.C . 

C.  C.  color  per  1000  lbs.  milk    Total  C.  C 

Ounces  salt  per  lb.  butter Total  lbs  . 

Time  starting  the  churn 

Time  churning  finished    

Size  of  granules 

Temperature  buttermilk    

Number  washings  given 

Temperature  1st Temperature  2d 

First  working,  numl)er  of  revolutions  of  churn 

No.  minutes 

Second  working,  number  of  revolutions  of  churn    

No.  minutes 

Interval  between  workings,  minutes 

Kind  of  packages  put  up 

Babcock  test  of  buttermilk 

Pounds  butter-fat  lost  in  buttermilk 

Remarks : 


(Signed)    

O.  K Instructor. 


Fig.  33.  —  Butter  Trier 

Butter  Scoring 


K3 


The  following  score  card  is  generally  used  for  scoring 
butter : 


46 


DAIRY  LABORATORY    GUIDE 
BUTTER  SCORE  CARD 


Perfect 


Flavor  45 


Texture 25 


Color 15 


Salt 


10 


Package  5 

Total   100 


1st  Scoring 
Date 


2d  Scoring 
Date 


Underscore  Defects 
Noted 


Curdy 

Light 

Rancid 

Fishy 

Feverish 

Oily 

Weedy 

Stable 

Unclean 

High  acid 

Low  acid 

Poor  grain 
Cloudy  brine 
Weak  body 
Too  much  brine 
Cheesy 
Tallowy 
Greasy 

Mottles 
White  specks 
Too  high 
Too  light 
Streaky  or  weavy 

f  Too  much  salt 
1  (Undissolved) 
•I  Poor  salt 
I  Lacks  salt 
1  Gritty 

f  Dirty 

I  Poorly  packed 
{  Poorly  nailed 
I  Poorly  lined 
^  Untidy 


Remarks : 


Judges 


Date. 


CHURNING 


47 


The  following  score  cards  proposed  by  B.  D.  White 
of  the  Dairy  Div.  Dept.  of  Agri.,  Washington,  D.  C, 
is  a  most  efficient  means  of  classifying  butter-makers 
and  grading  creameries.  Score  the  College  Creamery 
and  members  of  the  Dairy  Class  accordingly. 

In  cooperation  with  Dairy  and  Food  Department  in  the  State  of  . . . 


CREAMERY    SCORE   CARD 


General  Ap- 
pearance of 
Premises,  20 


Outside,  8 


Inside,  12. 


Scale,  Score 


^  Driveways  and 
Grounds. .  .  . 
j  Platforms  .... 
I  Out  Buildings. 
1    Painting 

[  Light 

j    Ventilation  . .  . 
[   Painting 


Flooi-s,  Construction  and  Condition   10 

Drainage  Disposal   10 


Machinery,  50 


Efficiency  and  Sufficiency  ...  10 

Arrangement 5 

State  of  Repairs    5 

Sanitary  Construction 20 

Durability 10 


Purity 8 

Water,  10 ...  .    j    Location    and    Condition      of 

Well 2 


Total. 


100 


48 


DAIRY   LABORATORY   GUIDE 
BUTTER-MAKER'S    SCORE    CARD 


Personal,  25. 


Ability,  7. .  . 
Training,  14 
Personal 


Scale,  Score 

Thoroughness      5 

Records 2 


Experience. 
Education . 
Tact 


Personal 
Cleanliness , 


^PP^^^^^^^'M  Clothing.....       2 

[.  Odor 
Grading  of  Raw  Materials,  15  . 


Odors 6 

Flavors 6 

Acidity 3 


Method  of 
Making,  50 


From   Weighing  Can  to  Cieani 

Vat 5 

f  Making  Starter  10 
Starter,  25 ...  .   i  Quality  of 

I      Starter 15 

Ripening  Cream 6 

Churning 4 

Working 4 

Moisture 4 

Preparation  of  Package 2 


Sanitary  Condition  of  Creamery 10 

Total 100 

Remarks.  —  Write  remarks  on  reverse  side. 

Name  of  Butter-maker 

Name  of  Creamery  


Post  Office County . 


State 


Inspector. 


Remarks.  —  Write  remarks  on  reverse  side. 


DETERMINATION  OF   THE   WATER  49 

EXERCISE  XIII 

Determination  of  the  Water  Content  of 
Butter 

Irish  Moisture  Test 

Read  carefully  the  following  explanations  and  test 
samples  of  butter  according  to  directions. 

Weigh  10  grams  of  butter  into  an  aluminium  cup 
upon  a  sensitive  scale.  Evaporate  the  water  by 
holding  the  cup  and  contents  over  the  flame  of  an 
alcohol  lamp.  Place  a  mirror  over  the  cup  to  catch 
and  condense  the  escaping  steam.  When  no  moie 
steam  condenses  on  the  mirror  the  sample  has  been 
boiled  long  enough.  Cool  and  weigh  again,  the  per- 
centage of  loss  being  calculated  and  considered  as 
water.  ^ 

Gray's  Method 

A  number  of  schemes  have  been  tried,  some  giving 
results  more  or  less  satisfactory,  but  one  only,  that 
of  Prof.  C.  E.  Gray  of  the  Dairy  Division  of  the 
Department  of  Agriculture,  Washington,  D.  C,  has 
been  perfected  to  such  an  extent  as  to  give  results 
which  seem  wholly  satisfactory.  With  this  method 
(requiring  apparatus  costing  only  a  few  dollars) 
any  one  of  average  intelligence,  after  a  few  trials, 
may  make  moisture  determinations  with  comparative 

'  The  weights  added  to  indicate  the  loss  in  weight  by  re- 
moval of  moisture  an^  so  marked  that,  by  adding  the  figures 
upon  them,  the  percentage  of  water  can  be  determined  direct. 


50 


DAIRY   LABORATORY   GUIDE 


accuracy.    The  test  is  described  by  Professor  Gray 
in  the  following  manner: 

Apparatus 

The  apparatus  required  for  making  the  test  is  as 
follows : 

Balances.  Sensitive  to  0.025  gram.  A  balance 
suitable  for  weighing  samples  of  cream  for  the  Bab- 


FiG.  34 

cock  test  should  be  satisfactory  for  w^eighing  samples 
of  butter  for  this  test;  however,  there  are  many 
cream  balances  in  use  which  are  not  accurate  enough 
for  weighing  either  cream  or  butter  samples. 

Weights.     One  5  gram  and  one  10  gram. 

Graduate.     For  measuring  6  c.c. 


DETERMINATION  OF   THE   WATER 


51 


Burner.  If  gas  is  not  readily  available  an  alcohol 
lamp  may  be  used. 

Paper.  Parchment  5  by  5  inches;  must  be  per- 
fectly dry. 

Special  Apparatus.  As  shown  in  figures.  Refer- 
ring to  figure  35,  ^4  is  a  flask  of  a  capacity  of  a  little 


z 

u. 

o  s 

^.! 

III  g 


N.Y. 


over  75  c.c.  (7  is  a  graduated  tube,  which  is  con- 
nected with  the  flask  A  by  means  of  a  rubber 
stopper  B;  F  is  Si  glass  stopper  ground  into  the 
tube  C.  Each  glass  stopper  is  ground  to  fit  a  par- 
ticular tube  and  will  not  properly  fit  other  tubes. 
Each  stopper  and  tube  should  be  marked,  by  the 


52  DAIRY  LABORATORY  GUIDE 

manufacturers,  to  eliminate  this  danger  of  using  a 
tube  with  a  stopper  which  has  not  been  ground  to 
fit.  The  tube  C  is  graduated  after  the  stopper  F  is 
ground  in,  the  zero  mark  being  the  end  of  the  stop- 
per. Each  mark  of  the  graduation  represents  one- 
fiftieth  c.c,  or  when  a  10-gram  sample  of  butter  is 
used  each  mark  represents  two-tenths  of  1  per  cent 
of  water.  E  is  a  glass  condensing  jacket  connected 
to  the  graduated  tube  C  by  rubber  stopper  D,  as 
shown  in  figure  35,  or  ground  onto  the  bulb  of  the 
tube  C  at  the  point  D,  as  shown  in  figure  34.  The 
apparatus  shown  in  figure  1,  having  the  condensing 
jacket  connected  by  means  of  a  rubber  stopper,  is 
the  form  which  seems  most  satisfactory  for  general 
use. 

Rubber  Stoppers.  The  rubber  stopper  B  will  be 
slowly  decomposed  by  the  heat  and  reagent  during 
the  process  of  making  the  tests.  As  a  stopper  is 
rendered  unfit  for  use  by  making  about  one  hundred 
determinations,  extra  rubber  stoppers  should  be 
obtained. 

Reagents 

Amyl  Reagent.  A  mixture  of  amyl  acetate  5 
parts  and  amyl  valerianate  1  part.  Must  be  free 
from  water-soluble  impurities  in  order  to  give  accu- 
rate results.  Users  not  in  position  to  test  this 
reagent  for  impurities  should  insist  on  a  tested 
article. 

Alcohol  (for  burning)  when  alcohol  lamp  is  used. 


DETERMINATION  OF   THE  WATER  53 

Making  a  Determination 

Preparing  the  Sample.  The  sample  of  butter  is 
placed  in  a  suitable  container  (1-pint  Mason  jar  or 
metal  cup  will  be  satisfactory).  This  container  is 
placed  in  water  at  about  100°  F.  The  butter  is 
stirred  with  a  spatula  or  spoon  until  it  is  about  the 
consistency  of  thick  cream  and  no  free  water  can  be 
seen.  Samples  of  butter  should  not  be  left  standing 
in  open  containers  any  length  of  time  before  making 
water  determination,  as  some  of  the  moisture  will 
evaporate  and  the  percentage  of  water  shown  when 
the  determination  is  finally  made  will  be  too  low. 

Weighing  the  Sample.  Place  on  each  pan  of  the 
balances  one  sheet  of  parchment  paper  and  balance 
accurately.  Place  the  10-gram  weight  on  one  pan 
and  balance  again  by  placing  butter  on  the  parch- 
ment paper  on  the  opposite  pan,  placing  the  sample 
as  near  the  center  of  the  paper  as  possible. 

Transferring  Sample  to  Flask.  When  exactly 
10  grams  are  weighed  out  remove  the  sample  from 
the  pan,  folding  it  in  the  parchment  paper  in  such  a 
shape  that  the  paper  and  butter  may  be  slipped  into 
the  flask  A.  Always  use  care  that  none  of  the  butter 
is  lost  in  transferring. 

Adding  Amy!  Reagent.  Fill  the  graduate  with 
amyl  reagent  to  the  mark  6  c.c,  first  being  sure  that 
the  graduate  is  free  from  water.  Place  the  6  c.c.  of 
amyl  reagent  in  the  flask  with  the  butter. 

Connecting  the  Apparatus.  Connect  the  appa- 
ratus as  shown  in  figure  1  and  fill  the  condensing 


54 


DAIRY   LABORATORY  GUIDE 


jacket  E  with  cool  water  to  within  one  inch  of  the 
top.     Remove  the  stopper  F, 

Distilling  off  the  Water.  Caution:  Be  sure  that 
the  glass  stopper  F  is  removed. 

Place  the  apparatus  over  the  flame  of  the  burner, 
applying  heat  to  the  bottom  of  the  flask  A.  In  a 
short  time  the  butter  will  melt,  running  from  the 
parchment  paper  into  the  amyl  reagent.    The  water 


Fig.  36.  —  Heating  the  sample  of  butter  with 
amyl  reagent  over  alcohol  flame. 

in  the  sample  then  boils  and  passes  as  steam  into  the 
tube  C,  where  it  is  condensed  and  trapped.  Watch 
the  condensation  in  the  graduated  part  of  the  tube 
C,  and  do  not  let  the  steam  get  higher  than  the 
15  per  cent  mark.  If  it  goes  higher  than  this,  remove 
the  flame,  as  there  is  danger  of  water  being  lost.  If 
there  is  any  indication  of  liability  of  the  mixture  in 
the  flask  A  foaming  over,  remove  the  flame.     Foam- 


DETERMINATION  OP  THE  WATER  55 

ing  is  usually  prevented  by  6  c.c.  of  amyl  reagent, 
but  some  samples  of  butter,  especially  those  of  high 
moisture,  require  a  trifle  more  than  6  c.c.  In  case 
of  continued  foaming,  allow  the  mixture  in  the  flask 
to  cool,  and  add  about  2  c.c.  of  the  amyl  reagent, 
and  continue  heating.  After  the  water  in  the  sample 
has  boiled  out,  the  temperature  rises  and  the  amyl 
reagent  boils,  driving  the  last  traces  of  water  and 
water-vapor  from  the  flask  and  bottom  of  the  stopper. 
Some  of  the  amyl  reagent  is  carried  into  the  tube  C 
with  the  steam,  and  some  is  boiled  over  after  the 
water  has  been  driven  off.  This  amyl  reagent  in  the 
tube  is  of  no  disadvantage. 

Determining  when  all  Water  has  Evaporated. 
The  time  required  for  driving  all  water  from  the 
sample  is  not  less  than  five  minutes  and  with  most 
samples  need  not  be  more  than  eight  minutes.  When 
the  mixture  in  the  flask  becomes  a  brown  color  and 
all  the  crackling  noises  in  boiling  cease,  it  is  safe  to 
conclude  that  all  water  has  been  driven  from  the 
flask. 

Disconnecting  the  Apparatus.  Disconnect  the  flask 
A  from  the  stopper  B,  place  the  glass  stopper  F 
in  the  tube  C,  giving  it  a  slight  turn  to  insure  its 
being  held  firmly;  invert  the  tube  C,  first  being  sure 
that  the  mouth  of  the  small  tube  inside  the  bulb  is 
held  upwards;  pour  the  water  from  the  condensing 
jacket  E,  after  which  the  jacket  may  be  removed. 

Separating  the  Reagent  from  the  Water.  When 
the  tube  C  is  inverted  the  water  and  amyl  reagent 
flow  into  the  graduated  part  of  the  tube.    To  separate 


56  DAIRY  LABORATORY  GUIDE 

these  and  to  get  the  last  traces  of  water  down  into 
the  graduated  part,  the  tube  C  is  held  with  the  bulb 
in  the  palm  of  the  hand  and  the  stoppered  end  away 
from  the  body,  raised  to  a  horizontal  position,  and 
swung  at  arm's  length  sharply  downward  to  the  side. 
This  is  repeated  a  number  of  times  until  the  dividing 
line  between  the  water  and  amyl  reagent  is  very 
distinct  and  no  amyl  reagent  can  be  seen  with  the 
water  or  vice  versa.  The  tube  should  then  be  held 
a  short  time  with  the  stoppered  end  downward  and 
the  amyl  reagent  in  the  bulb  of  the  tube  agitated  in 
order  to  rinse  down  any  water  that  may  be  adhering 
to  the  sides  of  the  bulb. 

Reading  the  Test.  The  reading  should  not  be 
taken  until  the  tube  and  its  contents  have  cooled 
so  that  very  little  warmth  is  felt.  The  water  is  in 
the  bottom  of  the  tube,  and  when  a  10-gram  sample 
is  taken  the  percentage  may  be  read  directly.  Read 
to  the  lower  part  of  the  meniscus. 

Other  than  lo-Gram  Samples.  With  butter  very 
low  in  moisture  it  may  be  desirable  to  take  a  15-gram 
sample,  and  with  butter  extremely  high  5-gram 
samples  may  be  used.  The  reading  multiplied  by 
ten  and  the  product  divided  by  the  weight  in  grams 
of  the  sample  taken  equals  the  percentage  of  water. 

Time  Required.  To  make  a  determination,  inclu- 
ding weighing  sample,  requires  from  fifteen  to 
twenty  minutes. 


DETERMINATION  OF  CASEIN  57 

Cleaning  the  Apparatus 

Flask.  The  flask  may  be  cleaned  by  washing 
with  soap,  washing  powder,  or  washing  soda  in  hot 
water.  It  is  not  absolutely  necessary  to  wash  the 
flask  after  each  determination;  the  residue  may  be 
poured  out  and  the  flask  wiped  with  a  cloth  or  thin 
paper.  The  flask  must  always  be  dry  (free  from 
water)  before  making  a  determination. 

Graduated  Tube.  After  making  the  test,  empty 
the  tube  C  by  holding  the  stoppered  end  downward, 
removing  the  stopper  and  allowing  the  contents  to 
flow  out  quickly.  In  this  way  the  amyl  reagent 
runs  out  after  the  water  and  carries  with  it  practically 
all  of  the  water,  which  might  otherwise  adhere  to 
the  tube.  The  tube,  after  emptying,  should  be  swung 
in  the  manner  described  for  separating  water  from 
amyl  reagent,  which  will  almost  completely  empty  it. 
Following  this  plan  it  is  not  necessary  to  dry  the 
tube  after  each  determination.  Occasionally  the 
tubes  should  be  washed  carefully  with  a  hot  solution 
of  sodium  carbonate  (sal  soda)  or  other  good  washing 
powder  and  thoroughly  dried  before  using. 

EXERCISE  XIV 

Determination    of    Casein,    Ash,    and    Salt    of 
Butter 

Carefully  weigh  a  dry  porcelain  dish  or  crucible  and 
place  thereon  a  sample  of  butter.  Weigh  and  sub- 
tract weight  of  dish.     Dissolve  ether  extract  (fat) 


58  DAIRY  LABORATORY  GUIDE 

by  addition  of  anhydrous  alcohol-free  ether.  Decant 
the  ether  and  repeat  until  the  fat  has  all  been  dis- 
solved. Allow  the  residue  to  dry  in  the  air  and 
weigh.  Cover  the  crucible  and  heat  gently  at  first, 
gradually  raising  the  temperature  to  just  below  red- 
ness. The  cover  may  then  be  removed  and  the  heat 
continued  till  the  contents  of  the  crucible  are  white. 
The  loss  in  weight  of  the  crucible  and  contents  repre- 
sents casein,  and  the  residue  in  the  crucible  mineral 
matter.  In  this  mineral  matter,  dissolved  in  water 
slightly  acidulated  with  nitric  acid,  chlorine  may  be 
determined  gravimetrically  with  silver  nitrate,  or 
volumetrically  after  dissolving  in  water  only,  using 
potassium  chromate  as  an  indicator.  From  the 
amount  of  chlorine,  CI,  present  the  quantity  of  salt, 
NaCl,  may  be  calculated  or  it  may  be  determined 
as  follows: 

Determination  of  Salt 

Weigh  in  a  counterpoised  beaker  from  5  to  10 
grams  of  the  butter.  The  butter  is  placed,  in  por- 
tions of  about  1  gram  at  a  time,  in  the  beaker,  these 
portions  being  taken  from  different  parts  of  the 
sample.  Hot  water  is  added  (about  20  c.c.)  to  the 
beaker  containing  the  butter,  and  after  it  has  melted 
the  liquid  is  poured  into  the  bulb  of  a  separating 
funnel.  The  stopper  is  inserted  and  the  contents 
shaken  for  a  few  moments.  After  standing  until  the 
fat  has  all  collected  on  top  of  the  water,  the  stopcock 
is  opened  and  the  water  is  allowed  to  run  into  an 
Erlenmeyer  flask,  care  being  exercised  to  let  none  of 


DETERMINATION  OF  CASEIN  59 

the  fat  globules  pass.  Repeat  extraction  from  ten 
to  fifteen  times,  using  from  10  to  20  c.c.  of  hot  water 
each  time.  The  resulting  washings  contain  all  but 
a  mere  trace  of  the  sodium  chloric!  originally  present 
in  the  butter.  The  sodium  chlorid  is  determined  in 
the  separated  fluid  by  a  standard  solution  of  silver 
nitrate,  AgNOg  using  a  few  drops  of  solution  of  po- 
tassium chromate  as  an  indicator. 

NaCl  +  AgNOe  =  AgCl + NaNOg. 

23.0  At.  wt.  of  Na 

35.5  At.  wt.  of  CI. 

58.5  Molecular  wt.  of  NaCl. 
For  every  35.5  CI  there  are  58.5  NaCl. 

\\Tien  a  permanent  reddish  brown  color  is  obtained, 
note  the  number  of  c.c.'s  used.  Each  c.c.  of  stand- 
ard solution  AgNOg  used  indicates  the  presence  of 
.0585  grams  of  salt. 

Example :  10  grams  butter  in  sample,  and  solution 
required  4  c.c.  AgNOg.  4 X. 0585  =.234  grams.  10 X 
.234  =  2.3  per  cent  salt,  or  .234-10X100  =  2.3  per 
cent. 

Method  for  the  Quantitative  Determination  of 
Proteids  of  Milk 

Bogg^s  Method 

Phosphtungstic  acid  in  hydrochloric  acid  solution 
precipitates  instantly  all  the  proteids  in  a  finely  di- 
vided condition.  The  precipitate  contracts  evenly  in 
a  vertical  direction  and  reaches  a  constant  minimum 


60  DAIRY   LABORATORY  GUIDE 

volume  within  twenty-four  hours.  The  supernatant 
fluid  is  perfectly  clear  and  gives  no  trace  of  proteid 
by  any  tests.  The  solution  which  seems  to  be  the 
optimum  is  composed  as  follows : 

Phosphotungstic  acid,  25  grams;  distilled  water, 
125  CO. 

After  thorough  solution  is  obtained  there  is  added : 

Hydrochloric  acid  (cone),  25  c.c,  diluted  with 
distilled  water,  100  c.c. 

This  yields  250  c.c.  of  a  10  per  cent  solution  of 
phosphotungstic  acid  in  about  3  per  cent  HCl.  The 
solution  is  quite  stable  if  kept  in  a  dark  bottle,  and 
gives  satisfactory  results  after  months  of  standing. 
It  is  desirable  that  the  components  be  mixed  as 
indicated,  i.e.,  the  well-diluted  HCl  added  after 
solution  of  the  phosphotungstic  acid  in  order  to  avoid 
precipitation. 

The  diluted  milk  is  poured  into  the  tube  to  the 
mark  U,  being  careful  to  read  from  the  bottom  of 
the  meniscus.  The  phosphotungstic  acid  solution  is 
added  to  the  mark  R,  the  tube  corked  and  slowly 
inverted  twelve  times  to  secure  thorough  mixing; 
care  being  had  to  avoid  shaking  roughly  and  thus 
mixing  air  in  the  fluid.  The  tube  is  then  placed  in 
a  rack  for  twenty  four-hours  and  the  percentage  read 
off  at  the  level  of  the  top  of  the  precipitate.  Fractions 
of  per  cent  between  the  graduations  are  readily 
judged  by  the  eye.  At  dilutions  of  1  part  in  10, 
percentage  of  proteid  is  read  directly  from  the  scale, 
while  if  the  dilution  be  1  in  20,  we  multiply  the 
reading  by  two;  if  1  in  5,  we  divide  by  two. 


CHEESE  MAKING 


61 


The  optimum  solution  for  human  milk  is  1  in  10. 
That  for  cow's  milk  1  in  20.  If  the  proteicl  content 
be  found  extremely  low  we  may  use  1  in  5  for  human 
milk  and  1  in  10  for  cow's  milk. 

The  minimum  volume  of  the  precipitate  is  reached 
in  twenty-four  hours.  Readings  at  thirty  and  forty- 
eight  hours  showed  no  appreciable  variations. 


COMPOSITION   OF  BUTTER 


Maximum 

Average 

Minimum 

Fat     

85% 
16% 

3% 
•75% 
•5% 
•2% 

84% 

12.8% 

2% 

•6% 

.4% 

.2<^ 

80% 

7% 

1% 
.6% 
.3% 
.1% 

Water                              

Salt    

Protein                 

Sugar 

Ash 

EXE] 

Chee 

EICISE  X 
SE  Makin 

V 

G 

Since  the  process  of  making  cheese  of  the  various 
kinds  is  based  upon  the  same  fundamental  principles, 
namely,  that  of  condensing  the  food  of  milk  by 
liberating  the  water,  we  will  merely  outline  the  process 
of  cheddar,  gouda,  and  cottage  cheese  making,  which 
are  most  commonly  used.  The  process  may  be  re- 
peated with  variations  in  acidity  of  milk  for  quicker 
or  slower  curing  cheese;  pressed  hard  or  merely 
drained,  for  hard  or  soft  cheeses,  and  cut,  salted, 
and  cured  in  various  methods  and  molds  for  the 
different  kinds  of  cheese  desired. 


62  DAIRY  LABORATORY  GUIDE 

Cheddar  Cheese 

Weigh  the  milk  to  be  used.  Take  accurate  sample 
for  fat  test,  acid  test,  and  rennet  test.  The  Marshall 
rennet  test  is  perhaps  the  most  commonly  used  in 
the  Cheddar  cheese  process,  although  the  Monrad 
test  is  very  efficient.  The  rennet  test  is  made  by 
filling  the  graduated  cup  to  the  zero  mark  with  milk 
at  86°  F.  Add  1  c.c.  pipette  full  of  5  per  cent 
rennet  solution.  Allow  the  milk  to  pass  through  the 
narrow  glass  bore  of  the  cup  and  note  amount  that 
passes  through  before  coagulation  begins.  The  riper 
the  milk  the  quicker  it  will  thicken,  with  a  corre- 
sponding less  reading  on  the  scales.  The  acidity  of 
the  milk  should  be  about  .2  per  cent  for  Cheddar 
cheese.  By  once  determining  the  acidity  of  the 
milk  and  the  corresponding  rennet  test  the  latter 
may  be  substituted  for  the  acid  test  in  the  following 
exercises.  If  milk  tests  less  than  .2  per  cent  acid  it 
may  be  ripened  with  starter.  After  reaching  the 
proper  acidity  pour  the  milk  into  vat  and  heat  to 
86°  F.,  the  temperature  at  which  rennet  works  best. 
Add  rennet  if  in  liquid  form,  two  to  four  ounces  to 
each  1000  pounds  of  milk;  if  in  tablet  form,  dilute 
one  tablet  in  one-half  pint  of  cold  water  and  pour  in 
as  indicated  on  directions.  If  pepsin  be  substituted 
for  rennet,  only  scale  pepsin  (strength  1-3000)  should 
be  used.  Use  .5  of  a  gram  for  every  500  pounds  of 
milk.  Dissolve  in  cold  water  before  adding  to  milk. 
Why?  Mix  thoroughly  and  allow  to  stand  until 
curdled  enough  to  break  clean  over  a  thermometer 


CHEESE  MAKING  63 

slanted  at  an  angle  of  45  degrees.  Cut  first  with 
horizontal  knife,  then  with  perpendicular  knife. 
Wire  stringed  knives  are  preferable.  Cook  curd  by 
heating  at  from  95°  F.  to  100°  F.  until  it  is  of  a  rub- 
bery consistency,  grits  between  the  teeth,  or  strings 
threads  one-eighth  inch  long  when  touched  to  a  hot 
iron.  This  usually  requires  one  and  one-half  hours 
from  time  rennet  is  added.  Stir  continuously  while 
cooking  to  prevent  matting  together  and  assist  curd 
in  heating  evenly.  Draw  off  whey  and  allow  curd 
to  mat  by  placing  on  curd  rack  for  five  to  ten  minutes 
until  firm  enough  to  handle,  then  pile  the  curd  about 
six  inches  deep  and  allow  that  to  drain  from  under- 
neath the  rack.  An  even  temperature  of  95°  F.  to 
100°  F.  must  be  maintained  to  keep  up  fermentation. 
After  ten  to  fifteen  minutes  the  curd  will  have  matted 
and  can  be  cut  into  blocks  which  are  frequently 
turned.  These  should  be  about  six  inches  wide. 
Turn  the  curd  so  as  to  facilitate  expulsion  of  whey, 
and  when  it  has  a  meaty  consistency  similar  to  that 
of  a  chicken's  breast  it  is  ready  to  mill.  Mill  when 
the  curd  becomes  flaky  and  shows  from  one  to  one 
and  a  half  inch  acid  (strings  one  to  one  and  a  half 
inches  long)  on  the  hot  iron.  If  curd  has  been 
tainted  it  may  be  improved  by  washing  with  water 
at  a  temi)erature  of  105°  F.  before  milling. 

There  are  numerous  kinds  of  curd  mills,  including 
the  Pig,  Pohl,  McPhearson,  Kasper,  and  the  Knife. 
The  Kasper  rotary  mill,  however,  is  generally  used. 
The  milling  should  be  done  about  an  hour  and  a  half 
after  drawing  whey,  and  the  salt  added  about  an 


64 


DAIRY  LABORATORY  GUIDE 


hour  and  a  half  after  milHng.     During  this  time  the 
temperature  should  be  kept  at  about  90°  F.     Why? 


The  curd  should  take  all   the    acid  it  will  before 
salting,  which  is  indicated  by  the  length  of  strings 


CHEESE  MAKING  65 

which  will  draw  out  on  a  hot  iron.  These  should  be 
about  two  inches  long.  Now  the  curd  is  ready  for 
salting.  It  should  be  soft  and  silky.  In  hot  weather 
reduce  the  temperature  as  much  as  possible  before 
salting  and  putting  the  curd  into  the  press.  Use  at 
the  rate  of  2\  to  2 J  pounds  of  salt  per  1,000  pounds 
of  milk,  varying  the  weight  of  salt  according  to  the 
amount  of  moisture  in  the  curd,  and  according  to 
market  demands.  Most  any  of  the  common  brands 
of  salt  are  very  good.  Worcester,  Anchor,  Ashton, 
Diamond,  Crystal,  Kansas,  Genesee,  Colonial,  and 
others  are  used.  To  determine  their  purity  dis- 
solve a  small  amount  of  salt  in  clear  water,  and  if  it 
remains  clear  there  is  no  dirt  present.  If  sediment 
settles,  or  if  cloudiness  is  produced,  impurities  are 
present.  Distribute  the  salt  evenly  by  mixing  with 
the  hands  or  forked  ladle.  Stir  every  ten  minutes 
to  keep  salt  from  settling  to  the  bottom  of  the  pile. 
Keep  at  90°  F.  When  a  velvety  feeling  is  regained, 
which  usually  requires  fifteen  to  twenty  minutes,  the 
curd  is  ready  for  pressing.  Cool  curd  to  between 
80°  and  85°  F.  Wiy?  Place  in  hoops  so  that  the 
bandages  are  even  with  edges,  turning  down  over  the 
circles.  Press  for  an  hour  by  tightening  press  every 
few  minutes.  The  curd  will  now  be  pressed  together 
and  it  should  be  taken  from  the  press  and  the  ban- 
dages smoothed  and  neatly  trimmed.  Soak  into 
position  with  warm  water  if  necessary.  Place  fol- 
lowers in  carefully  so  as  to  make  uniform  shape. 
Press  from  twelve  to  twenty-four  hours,  depending 
on  the  size  of  the  cheese  and  the  pressure.     Take 


66 


DAIRY  LABORATORY  GUIDE 


from  press  and  place  in  cooling  room  for  about  five 
to  ten  days.  Dip  in  melted  paraffin  at  200°  F.  to 
250°  F.  and  place  in  cooling  room  at  from  40°  to 
60°  F.,  having  a  humidity  of  from  65  to  80  per  cent 
(which  is  the  amount  of  saturation),  depending  on 


38.  —  Vat  for  Paraffining  Cheese 


the  temperature  and  length  of  time  desired  to  cure. 
The  per  cent  of  moisture  should  be  as  high  as  possible 
without  causing  a  growth  of  mold.  The  humidity 
of  the  curing  room  is  determined  by  a  psychrometer. 
The  psychrometer  is  more  reliable  than  the  hy- 


CHEESE  MAKING  67 

grometer  (or  hygroscope)  and  consists  of  two  ordinary 
thermometers  fastened  side  by  side  with  a  cup  and 
wick,  or  tube  of  water  between,  the  latter  being 
turned  at  the  bottom  in  the  form  of  a  small  cup  and 


Psychrometer 


closed  at  the  top  to  prevent  the  water  from  running 
away.  In  the  stationary  psychrometer  the  cup  end 
contains  a  wick  which  also  covers  the  bulb  of  one  of 
the  thermometers.    The  temperature  shown  by  this 


68 


DAIRY  LABORATORY  GUIDE 


thermometer  is,  of  course,  lowered  more  or  less  accord- 
ing to  the  rate  of  evaporation  from  the  wick,  and  this 
rate  is  affected  by  the  relative  humidity  of  the  air. 
In  a  saturated  air  there  could  be  no  evaporation  and 
the  thermometers  would  register  alike;  in  a  very  dry 
air  the  evaporation  would  be  rapid  and  the  difference 
of  temperature  indicated  would  be  considerable. 


Table  Showing  the  Relative  Humidity  in  the 
Air  of  Curing  Rooms.     (King.) 

Directions :  Notice  that  the  table  is  in  three-column 
sections.  Find  air  temperature  in  first  column,  then 
find  wet  bulb  temperature  in  second  column,  same 
division.  In  third  column  opposite  this  is  relative 
humidity. 

Example:  Air  temperature  is  50°  in  first  column; 
wet  bulb  is  44°  in  second  column,  same  division. 
Opposite  44°  is  61,  which  is  the  per  cent  of  saturation, 
or  relative  humidity  of  the  air. 

FAHRENHEIT  SCALE 


Dry 

Wet 

Rel. 

Dry 

Wet 

Rel. 

Dry 

Wet 

Rel. 

Dry 

Wet 

Rel. 

bulb 

bulb 

hum. 

bulb 

bulb 

hum. 

bulb 

bulb 

hum. 

bulb 

bulb 

hum. 

32 

31 

34 

29 

36 

28 

39 

32 

33 

38 

35 

36 

37 

34 

40 

37 

34 

46 

36 

43 

38 

40 

41 

43 

35 

53 

37 

49 

39 

46 

42 

49 

41 

36 

60 

44  » 

38 

56 

47 

40 

52 

50 

43 

55 

37 

68 

39 

63 

41 

59 

44 

61 

38 

76 

40 

70 

42 

66 

45 

67 

39 

84 

41 

78 

43 

72 

46 

74 

40 

92 

42 

85 

44 

79 

47 

80 

43 

92 

45 
46 

86 
93 

48 
49 

87 
93 

CHEESE  MAKING  69 

To  Prepare  Table  for  Psychrometer  Reading. 

See  W.  B.  Bulletin  No.  235,  Department  of  Agri- 
culture, Washington,  D.  C,  or  Smithsonian  Physio- 
logical tables,  p.  155. 

Observe,  1,  psychrometer  reading;  2,  dew  point. 

From  table  referred  to  determine  relative  humidity 
as  follows:  (from  dew  point  reading):  Example: 
If  dew  point  -  10°  C.  (50°  F.)  and  temperature  of 
air  =  30°  C.  (86°  F.)  the  weight  of  saturated  vapor 
in  air  at  10°  C  =  9.33  grm.  per  c.  m.;  the  weight  of 
saturated  vapor  in  air  at  30°  C  =  30.04  grm.  per  cm. 

(This  table  was  made  for  the  sHng  psychrometer 
and  does  not  exactly  correspond  to  the  one  on  the 
opposite  page.) 

Relative  Humidity = -^ =31.1% 

Then  prepare  table: 

Dry  Bulb  Wet  Bulb  Rel.  Hum. 

30°C  18°C  31.1°C 

Moisture  can  be  supplied  by  sprinkling  the  floor, 
or  better  still,  by  hanging  up  wet  sheets  that  are 
constantly  supplied  with  water. 

To  supply  a  curing  room  of  5000  cubic  feet  capacity 
at  least  3  cloths  30  inches  wide  by  12  feet  long  are 
needed.  To  keep  them  saturated  with  water  hang 
them  on  pipes  with  fine  holes  drilled  on  the  upper 
side,  and  a  gutter  below  to  carry  off  the  surplus 
drippings.  When  the  cloth  gets  stiff  from  sediment, 
boil  it  in  water  to  which  a  Httle  hydrochloric  acid 
has  been  added. 


70  DAIRY  LABORATORY   GUIDE 

In  cold  weather,  when  the  curing  room  is  artificially 
heated,  there  is  rarely  any  danger  of  the  air  in  it 
being  overladen  with  moisture;  and  there  is  little 
danger  of  this  in  summer  if  the  room  is  cooled  arti- 
ficially by  air  circulation  through  an  ice  chamber, 
because  the  air  in  passing  over  the  ice  is  cooled  to  a 
point  at  which  it  can  contain  little  moisture  in  com- 
parison to  its  capacity  when  at  the  higher  temperature 
of  the  room.  But  when  the  curing  room  is  not 
artificially  cooled  by  refrigeration  it  may  often  in 
summer  be  overladen  with  moisture. 

Air  at  20°  F.  may  contain  1.30  grains  of  water  to 
the  cubic  foot,  while  at  30°  it  may  contain  1.97 
grains,  at  40°  2.86  grains,  at  50°  4.09  grains,  at 
60°  5.76  grains,  at  70°  7.99  grains,  at  80°  10.95 
grains,  at  90°  14.81  grains,  and  at  100°  19.79  grains. 

Cheese  should  be  cured  for  from  six  weeks  to  a 
year,  depending  on  the  kind  of  cheese,  market  re- 
quirements, temperature  of  curing  room,  and  condi- 
tion of  cheese  when  made.  The  lower  the  uniform 
temperature  at  which  cheese  can  be  ripened  eco- 
nomically the  better  will  be  the  texture  and  quality  of 
the  cheese  and  the  less  will  be  the  loss  in  weight  dur- 
ing the  ripening  process.  The  cheese  score  card  is 
as  follows: 


CHEESE  MAKING  71 

Yield  of  Cheese  from  Milk  Varying  in  Richness 

Lbs.  milk  Per  cent  fat  Yield  of  cheese 

100  .1  5.5 

100  1.  6.7 

100  2.  8. 

100  3.  9.2 

100  4.  10.9 

100  5.  12.4 

Flavor 50 

Texture 25 

Salt 10 

Color 10 

Package    5 

a  00  Total 

A  good  flavor  should  not  be  sharp  so  that  it  will  bite 
the  tongue,  but  of  a  mild  lasting  taste  and  aroma. 
Texture  comes  next  in  importance.  A  good  texture 
can  be  determined  as  follows:  The  plug  should  be 
smooth,  not  fuzzy.  If  the  cheese  is  riot  fully  cured 
the  plug  should  bend  a  little  before  breaking.  When 
held  between  the  eye  and  the  light  it  should  be 
slightly  translucent.  If  the  light  does  not  come 
through  it,  it  is  a  sign  of  too  much  acid.  If  the  plug 
has  round  holes  in  it  too  little  acid  has  been  given  the 
curd.  When  pressed  between  the  fingers  it  should 
not  stick  to  them  but  mold  like  wax.  Cheese  should 
not  be  mealy  as  is  the  case  with  highly  acid  or  too 
highly  salted  cheese.  Color  comes  next.  It  should 
be  straight  and  translucent.  Then  comes  make-up. 
A  cheese  should  have  square  edges  evenly  bandaged 
and  clean.  Make-up  adds  considerable  to  selling  value 
of  cheese  as  well  as  appearance. 


72  DAIRY  LABORATORY  GUIDE 

EXERCISE  XVI 

GouDA  Cheese 

Repeat  Exercise  XV,  using  milk  containing  less 
than  .2  per  cent  acid.  Do  not  use  curd  mill,  but 
press  without  milling  or  salting.  After  pressing  suffi- 
ciently place  cheese  in  a  saturated  salt  solution. 
Brine  should  be  strong  enough  to  float  cheese.  Keep 
entirely  immersed,  or  turn  every  six  hours  until  rind 
forms.  This  usually  requires  about  twenty-four 
hours. 

EXERCISE  XVII 

Cottage  Cheese 

Ripen  100  pounds  skim  or  whole  milk  to  .8  or 
.9  per  cent  acid.  Place  in  vat  and  heat  to  95°  F. 
When  whey  is  sufficiently  liberated  draw  off.  Drain 
curd  in  cheese-cloth  until  most  of  the  whey  is  re- 
moved and  cheese  can  be  molded.  A  small  amount 
of  cream  mixed  into  the  curd  adds  materially  to  its 
palatability.  Salt  to  taste  and  mold  in  desired 
form.  With  similar  variations  the  following  cheeses 
may  be  made,  but  there  is  seldom  time  during  the 
short  course  to  make  more  than  three  or  four  different 
kinds.  Nor  is  it  practical,  for  the  main  difference 
between  some  of  them  is  the  name  of  the  county, 
province,  or  town  in  which  they  are  made,  with  only 
a  sHght  difference  in  method  of  manufacture  or  curing. 
Various  cultures  of  molds  and  bacteria  are  frequently 
employed  in  the  latter. 


SOFT  CHEESE  73 

The  following  is  a  list  of  some  of  the  different  kinds 

of  cheese : 

SOFT  CHEESE 

Brick  cheese United  States 

Cottage  cheese United  States. 

Brickbat  cheese England. 

SHpcoat  cheese    England. 

Fromage  blanc  (white  cheese)    France. 

Cream  cheese France. 

Double  cream  cheese    France. 

Coulommier  cheese  France. 

Bondou  cheese France. 

Fromage  de  Marseilles  cheese   France. 

Pont-L'Eveque  cheese France. 

Void  cheese    France. 

Cantal  cheese France. 

Livarot  cheese France. 

Menster  cheese France. 

Gerome  cheese France. 

Mont  d'Or  cheese    France. 

Brie  cheese France. 

Camembert  cheese    France. 

Roquefort  cheese France. 

Neufchatel  cheese     France. 

D'Arles  cheeselets  France. 

Brinsen  cheese Hungary. 

Mascarporie  cheese  Italy. 

Fromaggio  fresco  di  Pecora  cheese Italy. 

Robbiola Italy. 

Parmesan  cheese Italy. 

Reggrom  cheese Italy. 

Vaclievin  cheese    Switzerland. 

Bellelay  cheese    Switzerland. 

Caerphilly  cheese Wales. 

Romatour  cheese Bavaria. 

Limburger  cheese   Belgium. 

Kaiserkace Germany. 


74  DAIRY   LABORATORY  GUIDE 

HARD  CHEESE 

Pineapple  cheese United  States. 

Cheddar  cheese England. 

Stilton  cheese England. 

Blue  Dorset  cheese  England. 

Cheshire  cheese    England. 

Rex  cheese France. 

Gruyere  cheese    France. 

Port  du  Solut France. 

Edam  cheese    Holland. 

Gorgonzola  cheese Italy. 

Cacio  cavolla  cheese  Italy. 

Gouda  cheese Holland. 

Whey  cheese    Norway. 

Blundeer  cheese Norway. 

Old  (Norwegian)  cheese Norway. 

Mysort  cheese    Sweden. 

Emmenthaler  cheese Switzerland. 

Schweitzer  cheese Switzerland. 

Danish  export  cheese  Switzerland. 

Schabzieger  (SapSago)  cheese Switzerland. 

Zieger  (albumin)  cheese Switzerland. 

Sera  Do  Estrella Portugal. 

THE   FOLLOWING   BLANK   FORM   MAY    BE   USED 
IN  CHEESE-MAKING 

Date    Weather 

Vat  No   

Condition  of  milk    

flavor  

temperature 

acidity 

per  cent  of  fat  

Pounds  milk  in  vat 

Starter,  amount  used 

kind    

condition 

Color,  amount    

kind     


ICE  CREAM  75 

Rennet  test    , 

Setting,  hour 

temperature    

acidity 

amount  rennet  or  pepsin 

Curd  cut,  hour 

Steam  turned  on,  hour 

Time  taken  to  raise  temperature  to   .   .   .   degrees 

Whey  drawn,  hour 

temperature    .  .  . 

acidity 

condition  of  curd 

pounds  of  whey    

per  cent  of  fat  in  whey 

Mining,  hour 

acidity 

Salted,  hour 

amount    

kind    

Put  to  press,  hour 

temperature 

condition  of  curd    

Time  in  press 

Number  cheese  made 

Pounds  cheese  made 

Temperature  of  curing  room 

Humidity  of  curing  room 

Remarks     

EXERCISE  XVIII 

Ice  Cream 

The  principle  of  ice-cream  making  is  the  incorpora- 
tion of  air  while  freezing  the  cream.  This  is  readily 
accomplished  by  the  use  of  the  ordinary  freezer,  which 
is  so  constructed  that  it  retains  the  cold  within  the 
outer  wooden  tub  and  imparts  it  to  the  cream 
through  the  inner  tin  cylinder. 


76 


DAIRY   LABORATORY  GUIDE 


Fig.  40.  —  Continuous  Ice  Cream  Freezer.  The  cream  flows 
into  the  first  compartment  from  the  supply  tank  and  com- 
ing in  contact  with  the  cold  disks,  in  which  brine  solution  is 
circulating,  at  once  commences  to  freeze.  As  the  disks  re- 
volve the  cream  is  kept  agitated.  The  metal  fingers  sus- 
pended between  the  disks  prevent  the  cream  from  freezing 
on.  From  the  first  compartment  the  partially  frozen  mix- 
ture overflows  into  the  second.  The  latter  compartment  is 
deeper  than  the  first,  and  contains  in  addition  to  the  freez- 
ing disks  a  revolving  screw  which  carries  away  the  cream 
as  fast  as  the  freezing  is  completed.  This  conveyor  extends 
about  18  inches  from  the  freezer  and  discharges  into  the 
packing  can. 


ICE  CREAM  77 

For  5  gallons  of  ice  cream  use  2J  gallons  of  20  per 
cent  cream,  2^  ounces  of  flavoring,  and  2J  pounds  of 
sugar.  Slight  variations  are  frequently  advanta- 
geous. Place  in  freezer  and  put  two  parts  of  finely 
pulverized  ice  to  one  of  salt  aroimd  the  cream  can. 
Salt  has  a  great  affinity  for  water  and  causes  the  ice 
to  melt  rapidly.  The  ice  changing  from  sohd  to 
liquid  absorbs  heat  rapidly.  The  heat  is  taken  from 
the  cream  and  the  latter  thus  reduced  to  freezing 
point.  Revolve  slowly  about  80  revolutions  per 
minute  until  cream  begins  to  freeze  so  as  to  avoid 
churning.  Then  turn  rapidly  120  to  140  revolutions 
per  minute  so  as  to  pulverize  it  and  make  a  fine 
grain,  and  at  the  same  time  incorporate  air  enough 
to  give  the  desired  overrun.  In  freezing  the  flavoring 
is  sometimes  weakened  and  it  is  therefore  desirable 
to  add  flavoring  as  soon  as  the  cream  begins  to  freeze. 
Keep  the  entire  top  of  can  continually  covered  with 
ice  while  freezing.  The  freezer  should  never  be 
stopped  until  the  freezing  process  is  finished,  as  lumps 
of  ice  may  form,  causing  a  granular  body.  When 
the  freezer  is  stopped  before  the  process  is  com- 
pleted, a  portion  of  the  air  incorporated  is  likely  to 
escape,  much  the  same  as  when  half-beaten  cream 
is  allowed  to  stand.  The  air  escapes  and  the  cream 
settles. 

Various  kinds  of  flavoring  and  crushed  fruits  are 
often  used  in  making  ice  cream  and  sherbets.  Fruit 
may  be  crushed  and  added  to  the  cream  just  before 
freezing,  the  same  as  flavoring  is  added.  The  use  of 
geletina  and  corn-starch  in  making  ice  cream  is  not 


78  DAIRY  LABORATORY  GUIDE 

to  be  recommended,  for  cream  made  with  their  use 
frequently  tastes  more  Uke  custard  than  ice  cream. 

Harlequin  or  Neapolitan  Ice  Cream 

Freeze  several  freezers  of  ice  cream  of  various 
colors,  say  one  of  chocolate,  one  of  strawberry,  one  of 
plain  vanilla,  and  one  of  carmine  color.  Freeze  until 
the  cream  flows  with  difficulty,  but  not  so  stiff  as  to 
crumble.  Spread  first  one  layer  the  desired  thickness, 
usually  about  one-half  inch,  then  another  of  different 
color  on  top  of  the  first,  and  so  on  until  the  cake  is 
complete.  Place  in  packer  and  allow  to  harden,  cut 
in  desired  form  and  serve. 

In  packing  ice  cream  take  the  latter  from  the 
freezer  with  a  ladle  and  deposit  with  a  swinging 
motion  against  the  periphery  of  the  packing  can 
which  has  been  thoroughly  cooled  by  placing  fine  ice 
and  salt  around  the  outer  space.  Thus  by  retain- 
ing the  incorporated  air  the  over-run  may  be  main- 
tained. 

Molding  Ice  Cream 

If  molds  are  used  the  cream  should  be  packed 
closely  into  them,  filling  every  crack  and  corner. 
The  cover  should  fit  over  and  not  into  the  mold. 
Smear  the  edges  with  paraffin  to  keep  out  salt  and 
water.  Bury  molds  in  crushed  ice  and  salt.  A 
slightly  smaller  proportion  of  salt  should  be  used 
than  in  freezing.  Cover  ice  with  wet  burlap.  Draw 
off  the  brine  as  fast  as  the  ice  melts.  Allow  to  stand 
for  an  hour  or  more  before  serving. 


DAIRY   BACTERIOLOGY 


79 


EXERCISE  XIX 
Dairy  Bacteriology 

Examine  microscope  carefully  under  the  direction 
of  the  instructor  and  ascertain  difference  between 
high  and  low  power  objectives  with  different  eye 
pieces.  Manipulate  reflector,  condenser,  and  dia- 
phragm to  ascertain  various  combinations. 


Fig.  41 

The  above  cut  represents  a  portion  of  a  drop  of 
milk  containing  F,  fat  globules,  L,  leucocytes,  Y, 
yeast,  and  B,  b,  c,  s,  T,  1  and  2,  seven  species  of 
bacteria  frequently  found  in  milk.  B  represents 
the  hay  bacillus  group  which  are  among  the  largest 
known  species  of  bacteria,  and  frequently  form 
chains;  b  represents  one  species  of  bacillus  viscosus 


80  DAIRY  LABORATORY  GUIDE 

which  forms  slimy  milk;  c  represents  a  common 
coccus  form;  s  represents  a  streptococcus  (forming 
chains);  T  represents  bacillus  typhosus;  1  represents 
tetragenococci,  and  2,  one  of  the  lactic  acid  group. 

Place  a  drop  of  water  on  a  clean  cover  glass  by 
means  of  platinum  wire,  then  touch  the  end  of  the  wire 
in  a  sample  of  milk,  mix  with  water  on  a  cover  glass, 
place  on  clean  slide  and  examine  under  microscope. 
The  water  dilutes  the  milk  enough  to  make  a  clear 
field.  Examine  for  fat  globules,  bacteria,  and  leucocy- 
tes, if  present.  The  latter  are  from  two  to  ten  times 
larger  than  fat  globules  and  an  irregular  outline.  Ex- 
amine samples  of  skim-milk  for  fat  globules.  Make 
hang-drop  shdes  and  examine  in  the  same  manner. 
To  find  the  correct  measurements  for  microscopic 
work  place  a  micrometer  in  the  eye  piece,  or  ocular, 
and  a  stage  micrometer  (which  equals  1-100  mm.) 
on  the  stage  of  the  microscope.  Determine  the  rela- 
tion of  the  divisions  of  the  former  to  those  of  the 
latter  by  making  the  initial  lines  coincide  and  count- 
ing the  number  of  divisions  of  the  stage  micrometer 
that  is  required  to  make  one  of  the  ocular  micrometer. 
Example :  where  a  J  power  ocular  is  used.  When 
13  divisions  of  ocular  equals  5  divisions  of  the  stage 
micrometer,  let  A  equal  stage  division,  and  0,  ocular 
division. 

13°  equals  5  s. 

1°  equals  138.. 

1^  equals  .01  mm. 
■f^  s  equals  .Ol''  equals  .003846  m.m. 


DAIRY  BACTERIOLOGY  81 

A  plain  slide  may  then  be  substituted  for  the  stage 
micrometer  and  all  measurements  taken  by  means  of 
the  ocular  micrometer. 

A  table  may  then  be  constructed  in  the  following 
manner  which  will  save  time  in  calculating  the  meas- 
urement of  objects : 

.5    division  .001923  m.m. 

.75  division  .002888  m.m. 

1.00  division  .003846  m.m. 

1.25  division  .004825  m.m. 

1.3    division  .005012  m.m. 

1.5    division  .005785  m.m. 

1.75  division  .006748  m.m. 

2.00  division  .007712  m.m. 

2.25  division  .008676  m.m. 

2.5    division  .009640  m.m. 

2.75  division  .010604  m.m. 

3.00  division  .011569  m.m. 

Prepare  a  clean  cover  glass  and  place  thereon  a 
drop  of  water.  Transfer  a  minute  portion  of  decayed 
material,  starter,  or  clabber  milk,  and  spread  uni- 
formly over  the  surface  of  the  glass  and  allow  film 
to  dry.  When  dry,  pass  cover  glass,  smeared  surface 
upward,  three  times  through  a  Bunsen  flame  at 
about  the  rate  of  a  pendulum  of  a  clock.  The  heat 
coagulates  the  albumen  around  the  bacteria  and  fixes 
them  firmly  to  the  glass.  Place  a  drop  of  staining 
solution  prepared  from  anilin  dyes  (gentian-violet, 
basic  f uchsin,  and  methylene  blue,  are  most  commonly 
used)  on  the  glass  and  allow  stain  to  remain  for  from 
two  to  ten  minutes,  depending  on  the  strength  of  the 
staining  solution  and  the  kind  of  bacteria.  Rinse  in 
water.     Dry    the   unsmeared   side   on   filter   paper, 


82 


DAIRY  LABORATORY  GUIDE 


mount  film  side  down  in  a  drop  of  water  on  clean 
slide  and  examine.  If  bacteria  are  properly  stained, 
dry  both  sides  with  filter  paper  and  mount  film  side 
down  in  a  drop  of  balsam.  liabel  and  preserve. 
Prepare  cultures  for  bacterial  growth  as  follows 
(after  Gorham) : 

PREPARATION  OF  CULTURE  MEDIA 


I.  Bouillon 


1.  Infuse  finely  chopped  lean 
beef  for  twenty  hours  with 
twice  its  weight  of  distilled 
water  in  the  refrigerator, 
say  1000  grams  of  meat, 
2000  grams  of  water. 

2.  Make  up  weight  of  meat- 
infusion  (and  meat)  to 
original  weight  by  adding 
water  —  i.e.,  to  3000  grams 

3.  Filter  infusion  through 
cloth  to  remove  meat. 

4.  Weigh  infusion,  say  1800 
grams. 

5.  Set  infusion  on  water-bath, 
keeping  temperature  below 
600  C. 

6.  Add  peptone,  1  per  cent, 
18  grams;  salt,  0.5  per 
cent,  9  grams. 


7.  After  ingredients  are  dis- 
solved, titrate  ;  2  reaction 
probably  +  2.3  to  +  2.5  per 
cent. 

8.  Neutralize. 


II.  Gelatine 


Ditto. 

Ditto. 

Ditto. 
Ditto. 
Ditto. 


Ditto,  and 
sheet  gela- 
tine, 10  per 
cent      180 
grams. 

Ditto,  proba- 
bly+4.0  to 
+  5.0  per 
cent. 

Ditto. 


III.  Agar 


Boil  30  grams  of  thread 
agar  in  1  liter  of  water  for 
half  an  hour.  Make  up  loss 
by  evaporation  to  a  weight 
of  1000  grams. 

1.  Infuse  finely  chopped  lean 
beef  for  twenty  hours  with 
its  own  weight  of  distilled 
water  in  the  refrigerator, 
say  1000  grams  of  meat, 
1000  grams  of  water. 

2.  Make  up  weight  of  meat- 
infusion  (and  meat)  to 
original  weight  by  adding 
water  —  i.e.,  to  2000  grams. 

3.  Ditto.  (See  3.) 

4.  Ditto,  say  900  grams.  (See 
4.) 

5.  Ditto.   (See  5.) 

6.  Add  peptone,  2  per  cent, 
18  grams;  salt,  1  per  cent, 
9  grams. 

7.  Ditto,  probably  +  4.5  to 

4.7  per  cent.    (See  7.) 

8.  Ditto. 

To  the  900  grams  of  meat- 
infusion  (containing  new  pep- 
tone and  salt)  add  900  grams 
of  the  3  per  cent  agar  jelly 
described  at  the  head  of  this 
column. 


DAIRY   BACTERIOLOGY  83 

Heat  over  boiling  water  or  steam  thirty  minutes. 
Restore  weight  lost  by  evaporation  to  original  weight 
for  bouillon  and  gelatine  and  twice  that  weight  for 
agar.  Titrate  and  adjust  reaction  to  the  final  point 
desired.  Sterilize  for  three  consecutive  days  so  as 
to  kill  all  germs  present,  and  fill  test  tubes  one-third 
full.     Cork  with  sterile  cotton  and  sterilize  again. 

Certain  species  of  bacteria  grow  sufficiently  well  on 
media  made  from  beef  extract  instead  of  lean  beef. 
The  former  requires  less  work  and  may  be  used  in 
the  following  proportions : 

Bouillon 

Beef  extract 3  grams 

Peptone 10  grams 

Salt    5  grams 

Water  1000  c.c. 

Gelatine 

Beef  extract 5  grams 

Peptone 10  grams 

Salt    5  grams 

Gelatine    100  grams 

Water    1000  c.c. 

Agar 

Beef  extract     5  grams 

Peptone 10  grams 

Salt   5  grams 

Agar    20  grams 

Water   1000  c.c. 

Make  potato  media  by  washing  sound  potatoes  and 
cutting  the  ends,  and  with  sterile  cork-borer  cut  out 
cylinders  of  the  potato  a  little  smaller  than  the  tubes 
to  be  used.     Handle  potato  under  water  as  much  as 


84  DAIRY  LABORATORY  GUIDE 

possible  to  prevent  darkening  of  surface.  Cut  cylin- 
ders into  two  equal  parts  by  a  diagonal  cut.  Place 
in  cool  running  water  for  twelve  to  eighteen  hours. 
This  usually  renders  the  potato  neutral.  Sterilize 
in  steam  sterilizer  for  thirty  minutes  on  three  con- 
secutive days.  Place  in  sterile  test  tubes,  slanting 
surface  upward,  and  plug  with  sterile  cotton.  Steri- 
lize once  after  plugging. 

Milk  Media 

Heat  fresh  milk  for  fifteen  minutes  in' steam  steri- 
lizer at  200°  to  212°  F.  Place  in  ice-box  over  night. 
Titrate,  and  if  less  than  .2  per  cent  acid  place  in 
tubes  and  sterilize  for  twenty  minutes  on  four  con- 
secutive days  in  a  steam  sterilizer.  If  more  than 
.2  per  cent  acid  reduce  to  .15  per  cent  by  the  addition 
of  one-tenth  normal  solution  of  sodium  hydroxide. 
Place  in  sterile  test  tubes  with  sterile  cotton  plugs. 
Make  cultures  of  the  above  media  from  milk,  cheese, 
ice  cream,  and  butter  from  various  sources.  Note 
behavior  and  color  of  culture  on  the  various  kinds 
of  media.  Make  plate  cultures  of  agar  and  gelatine 
by  warming  them  to  melting  point  and  adding  a 
drop  of  milk.  Shake  thoroughly  and  pour  into  sterile 
petra  dish  and  allow  to  cool.  Place  in  incubator  for 
twelve  to  twenty-four  hours  at  100°  F.  in  case  of  the 
agar  plates  and  80°  F.  in  the  case  of  gelatine  plates. 
Examine  every  few  hours  or  as  often  as  convenient. 

Make  medium  more  condensed  for  quantitative 
analysis  of  liquids. 

After  washing  with  cleaning  mixture  prepared  in 


DAIRY  BACTERIOLOGY  85 

* 

Exercise  I,  sterilize  all  empty  glassware  for  at  least 
thirty  minutes  at  a  temperature  of  212°  F.  in  a  dry 
air  sterilizer.  After  turning  off  the  gas  allow  uten- 
sils to  remain  in  steriUzer  for  ten  minutes  before 
opening  the  door.  Otherwise  the  cool  air  coming 
suddenly  in  contact  with  the  hot  glass  may  cause 
some  of  the  parts  to  crack. 

Before  steriHzing  pipettes  wash  each  one  thoroughly, 
and  while  the  ends  are  moist  roll  a  piece  of  clean 
cotton  to  a  point  and  insert  in  the  end  of  pipette. 
Turn  the  remaining  part  of  the  cotton  back  over  the 
pipette,  and  if  the  latter  is  moist  it  will  wrap  tightly 
around  the  same  between  the  thumb  and  fore-finger 
while  revolving  the  pipette  with  the  thumb  and  fore- 
finger of  the  other  hand.  Repeat  the  operation  with 
the  other  end  of  the  pipette. 

When  using  sterile  pipette  hold  in  vertical  position 
and  pull  lower  plug  first.  This  prevents  contami- 
nation to  a  great  extent. 

The  media  must  all  be  sterilized  in  a  steam  steriUzer 
in  order  to  prevent  evaporation.  SteriUze  at  212° 
F.  thirty  minutes  for  three  consecutive  days  to  kill 
all  bacteria  which  are  likely  to  germinate  from  the 
spores  which  resist  boiling  temperature. 

Make  a  quantitative  analysis  of  bacteria  in  a 
sample  of  whole-milk  by  drawing  into  a  delicately 
graduated  pipette  .1  c.c.  of  the  milk  to  be  analyzed. 
Transfer  this  into  a  sterile  water  blank  test  tube 
containing  .9  c.c.  of  sterile  water.  After  shaking 
well,  transfer  .1  c.c.  of  this  in  the  same  way  to  a  test 
tube    containing   sterile    melted    agar    media.     Mix 


86  DAIRY   LABORATORY  GUIDE 

well  and  pour  into  a  petra  dish.  The  solution  will 
then  contain  .01  c.c.  of  milk,  and  the  number  of 
colonies  that  develop  in  the  petra  dish  is  therefore 
multiplied  by  100  to  obtain  the  average  number  of 
bacteria  per  cubic  centimeter. 


Fig.  42.  —  Culture  of  1-100  c.c.  milk  from  separator  which 
had  been  flushed  with  warm  water  only. 


Measure  from  .1  to  1  c.c.  of  milk  into  test  tubes 
containing  5  c.c.'s  sterile  water  (water  blanks).  To 
a  given  number  of  these  add  5  c.c.  of  washing  powder 
in  solution.  Pour  contents  of  each  tube  into  test 
tubes  containing  melted   agar.     Shake    thoroughly 


DAIRY   BACTERIOLOGY 


87 


and  pour  into  petra  dishes.  The  number  of  colonies 
that  develop  in  each  indicates  the  efficiency  of  the 
disinfectant.  The  smaller  the  number  of  colonies 
the  more  efficient  the  washing  powder. 


Fig,  43.  —  Culture  of  1-100  c.c.  milk  from  average 
ized  separator, 


steril- 


Repeat,  using  a  small  speck  of  manure  or  dirt  from 
your  finger  nail.  Also  make  plate  cultures  from  a 
drop  of  milk  taken  from  a  cow  at  beginning  and  last 
part  of  milking.  Make  plate  exposures  by  filling 
petra  dishes  with  melted  agar  and  allowing  to  soUdify. 
Expose  one,   two,   and   three  minutes  in  open  air, 


88  DAIRY  LABORATORY  GUIDE 

barn,  dairy,  and  various  places  of  interest.  Place  in 
incubator  as  before  and  note  results.  Determine  gas 
fermentation  by  use  of  curd  test  and  also  by  placing 
sterile  bouillon  in  fermentation  tubes.    A  small  test 


Fig.  44.  —  Shows  a  plate  exposed  one-half  minute  during 
the  process  of  milking,  under  cow's  udder  treated  by 
merely  brushing  with  the  hand.  Each  of  the  little 
spots  represents  a  colony  of  some  kind  of  bacteria. 

tube  inverted  inside  of  a  large  one  will  answer  for  a 
fermentation  tube.  Add  a  few  drops  of  milk  or 
cream  to  be  tested  and  allow  to  remain  at  100°  F. 
for  twelve  to  twenty-four  hours,  and  note  amount  of 
gas  collected. 


MILK  PAINT 


89 


Fig.  45.  —  Shows  a  plate  exposed  one-half  minute  during 
process  of  milking,  under  a  cow's  udder  treated  with  a 
5  per  cent  solution  of  carbolic  acid.  The  animal  was  on 
a  cement  floor  and  bedding  was  present.  It  will  be  noted 
this  plate  is  quite  an  improvement  over  plate  shown  in 
Fig.  44. 

EXERCISE  XX 

Milk  Paint 

Stir  into  one  gallon  of  skim-milk  3  pounds  of 
Portland  cement  and  add  sufficient  paint  powder 
to  impart  desired  color,  and  apply  to  board  or  fence 
post  while  thoroughly  mixed.  Note  the  effect  of 
this  paint  upon  standing  in  vessel  and  the  necessity 
of  constant  stirring  while  being  used.  Repeat  the 
experiment,  using  a  small  amount  of  carbolic  acid  or 


90  DAIRY  LABORATORY  GUIDE 

other  disinfectant  and  apply  to  a  board  or  fence  post 
in  the  same  vicinity.  On  the  following  day  secure 
cultures  from  the  posts  and  determine  by  means  of 
plate  cultures  the  difference  in  the  number  of  the 
bacteria  obtained  from  the  two  sources. 

EXERCISE  XXI 

Tests  for  Preservatives 

ECHO  +  H^O 

Add  one  drop  of  formaldehyde  to  }  pint  of  milk 
and  shake  thoroughly.  Obtain,  by  means  of  a  pipette, 
17.6  c.c.  or  any  convenient  amount  of  the  milk,  and 
place  in  Babcock  test  bottle.  Add  a  similar  amount 
of  sulphuric  acid  and  allow  to  stand  quietly  for  five 
minutes.  Note  color  line  at  junction  of  acid  and 
milk,  which  should  be  a  distinct  purple  or  violet, 
indicating  the  presence  of  formaldehyde.  Repeat  the 
experiment  using  concentrated  hydrochloric  acid. 
Also  add  a  few  drops  of  ferric  chloride  to  aid  the  color 
reaction.  Formaldehyde  is  a  colorless,  volatile  liquid 
chemically  intermediate  between  methyl  alcohol  and 
formic  acid.  When  consumed  with  milk  it  produces 
various  intestinal  disturbances,  and  if  present  in 
excessive  amounts  produces  poisoning. 

Test  for  Boracic  Acid.     H3BO3 

Place  i  gram  or  any  convenient  amount  of  borax 

in  a  pint  of  milk  and  shake   thoroughly.     Obtain 

sample  of  milk  by  means  of  pipette  and  place  in 

small  porcelain  dish.     Evaporate  about  one-half  to 


TEST  FOR  OLEOMARGARINE  91 

concentrate  amount  of  borax  present.  Add  as  much 
alcohol  as  there  is  milk  present,  and  ignite.  A  green 
flame  indicates  the  presence  of  borax. 

Test  for  Salicylic  Acid.    CeH.O-HCOOH 

1.  Place  a  few  crystals  of  saHcyUc  acid  in  i  pint 
of  milk  and  agitate  thoroughly  as  in  the  previous 
tests.  Pour  a  small  quantity  of  same  in  test  bottle 
and  add  about  the  same  quantity  of  sulphuric  acid, 
with  about  30  c.c.  of  chloroform  or  ether.  These 
dissolve  the  fat  present  and  greatly  facilitate  the 
test.  Add  a  few  drops  of  ferric  chloride.  The  pres- 
ence of  salicylic  acid  is  indicated  by  a  purple  or 
violet  color  similar  to  that  of  formaldehyde.  The 
distinction  between  these  tests  being  that  the  color 
reaction  does  not  appear  in  the  presence  of  salicylic 
acid  unless  ferric  chloride  (FejCle)  be  used,  but  ap- 
pears in  the  presence  of  formaldehyde  in  either  case. 

2.  Place  5  c.c.  suspected  solution  in  porcelain  dish 
and  evaporate  to  dryness.  Warm  residue  with  one 
drop  of  concentrated  nitric  acid.  Add  two  or  three 
drops  of  ammonia  until  alkaline.  The  presence  of 
salicylic  acid  is  indicated  by  the  formation  of  a 
yellow  color  or  ammonium  picrate  which  will  dye  a 
thread  of  fat  free  wool. 

EXERCISE   XXII 

Test  for  Olp:omargarine 

Place  5  grams  or  any  convenient  amount  of  oleo- 
margarine in  a  small  dish  and  apply  flame.     Place  in 


92  DAIRY  LABORATORY  GUIDE 

another  dish  a  similar  quantity  of  butter.  Note  the 
difference  in  the  manner  in  which  they  melt.  The 
oleomargarine  sputters  like  grease  in  a  frying-pan  on 
account  of  the  excessive  amount  of  water  present. 
It  does  not  foam,  however,  as  much  as  the  butter. 
The  butter  melts  quietly  and  foams  a  great  deal. 
Also  note  odor  of  lard  in  oleomargarine.  Score  a 
sample  of  each  for  flavor,  texture,  grain,  and  body. 

Test  for  Renovated  Butter 

Repeat  test  for  oleomargarine  and  note  the  simi- 
larity with  which  renovated  butter  melts.  The  dis- 
tinction between  the  two,  however,  lies  in  the  fact 
that  when  added  to  a  small  amount  of  milk  reno- 
vated or  any  other  kind  of  butter  may  be  incorpo- 
rated into  the  milk  by  heating  and  stirring.  The  fat 
from  oleomargarine,  on  the  other  hand,  cannot  be 
incorporated  into  the  milk.  If  stirred  while  cold 
into  cold  milk  the  butter  will  form  in  small  flakes  or 
grains  in  the  milk,  while  oleomargarine  will  collect 
in  a  ball.  The  fat  from  good  butter  will  crystalhze 
out  more  perfectly  than  that  of  renovated  butter. 
The  latter  has  a  very  poor  grain  and  body,  the  grain 
having  been  destroyed  in  processes  of  renovation. 

EXERCISE  XXIII 

Repairing  Creamery  Machinery 

Repair  broken  belts  by  cutting  broken  ends  of 
belt  square  so  that  the  parts  come  evenly  together. 


REPAIRING  CREAMERY  MACHINERY  93 

Punch  holes  in  a  line  one  inch  from  cut  edges,  the 
number  depending  on  width  of  the  belt.  They  should 
be  about  one  and  one-half  inches  apart.  Punch  the 
back  holes  one  and  one-half  inches  from  first  row 
and  directly  between.  Begin  lacing  at  middle  of 
belt.  Be  careful  to  have  smooth  side  of  lacing  next 
pulley.  The  ends  are  fastened  by  running  them 
through  small  holes  punched  in  line  with  the  lace 
holes.  Repair  broken  belt  with  steel  wire  lacing  by 
using  only  one  row  of  holes  on  each  end  of  belt. 
Also  repair  with  steel  belt  lacing. 

Repair  broken  belts  with  glue  by  cutting  each  end 
off  squarely  and  then  cut  widthwise,  a  slant  beginning 
back  two  inches  from  edge  of  belt,  and  slant  to  a 
narrow  edge.  Glue  slanting  surface  of  both  ends. 
Place  together  and  press  until  dried.  Determine  the 
efficiency  of  the  four  methods  by  daily  use. 

Determine  speed  of  main  shaft  and  pulleys  on 
machinery  by  the  following  fornmla : 

To   Determine  Diameter  of  Pulley  on  Main  Shaft 

When  the  speed  of  engine  pulley  is  1000  revolutions 
per  minute,  the  diameter  of  the  engine  pulley  is  5 
inches  and  the  speed  of  the  main  shaft  is  180  revolu- 
tions per  minute. 

1000  X  5  -  180  =  27.7  inches. 

To  determine  the  speed  of  the  main  shaft  when  the 
diameter  of  pulley  on  main  shaft  and  diameter  and 
speed  of  engine  pulley  is  given  as  in  above  example. 
1000  X  5  ^  27.7  =  180 


94 


DAIRY  LABORATORY  OVIDE 


Line  up  shaft  by  fastening  chalked  string  along 
ceiling  parallel  to  direction  of  shafting.  Snap  string 
and  put  hangers  up  loosely  in  line  with  chalk  mark. 
Place  shaft,  arranging  its  position  in  hangers  in  a 
plane  parallel  to  the  floor,  and  fasten  hangers  and 
shaft  securely.  Line  up  machinery  to  shafting  by 
holding  one  end  of  string  so  that  it  touches  both 
sides  of  pulley  on  shaft  and  tight  pulley  on  ma- 
chine. 

Repair  worn  valves  by  repacking  and  grinding 
when  worn. 

Repair  cement  floor  by  thoroughly  mixing,  while 
dry,  one  part  of  cement  to  two  of  sand.  Moisten 
with  water  until  thoroughly  wet  but  without  excess 
of  water.  Apply,  press  thoroughly,  and  smooth  with 
trowel.  If  corners  of  dairy  floor  are  not  rounded, 
fill  in  with  cement  and  smooth  neatly  as  shown  in 
Fig.  5. 

Adjust   a   small   electric    battery   with   bell    and 

switch  connections 
above  the  milk  vat  and 
attach  a  string  with 
float  on  one  end  and  a 
weight  on  the  other,  as 
shown  in  accompany- 
ing cut.  When  the  milk 
is  being  pumped  or 
drawn  from  the  vat  to 
the  separator  or  pas- 
teurizer, the  float  will  lower  until  the  weight  on  the 
opposite  end  of  the   string  touches   the  break   and 


THE  MODIFICATION  OF  MILK 


95 


rings  the  bell,  thus  notifying  the  operator  that  the 
tank  is  almost  empty. 

F  represents  float.  6,   brake. 

T,  tank  or  vat.  s,    switch. 

w,  weight.  B,  battery. 

See  that  everything  is  arranged  for  convenience, 
neatness,  and  sanitation,  and  that  there  is  no  un- 
necessary waste.  All  corners,  joints,  seams,  and 
crevices,  in  any  apparatus  in  which  milk  or  cream 
is  to  come  in  contact  should  be  smoothly  soldered. 
See  ^'Creamery  Conveniences"  Exercise  35. 

EXERCISE  XXIV 

The    Modification    of    Milk    for    Infants    and 
Invalids 

The  following  is  the  average  composition  of  various 
kinds  of  milk: 


Cows 

Sheep 

Goats 

Mares 

Human 

Commercial     Sweetened 

Condensed  Milk 

Commercial     Condensed 

Milk,  Unsweetened 


Water 

Sugar 

Protein 

Fat 

87% 

5% 

3.3% 

4% 

83.5 

3.96 

5.74 

6.14 

86.91 

4.45 

3.69 

4.09 

90.06 

6.65 

1.89 

1.09 

88.2 

6.8 

1.50 

3.3 

27.25 

12.50 

8.63 

9.13 

70.44 

10.96 

8.35 

8.71 

Ash 

.7% 

.66 

.86 

.31 

.20 

1.75 

1.54 


Very  few  invalids  or  infants  are  constituted  exactly 


96 


DAIRY  LABORATORY  GUIDE 


alike,  and  therefore,  although  the  upper  third  of  milk 
in  combination  with  barley  water,  etc.,  is  frequently 
advocated  for  such  use,  it  must  be  modified  to  suit 
the  individual.  In  many  cases  peptone  in  the  form 
of  peptogenic  milk  powder  must  be  added  to  partially 
digest  the  casein. 

The  average  diet  for  infants,  with  variations  to 
meet  individual  demands,  should  be  as  follows: 

Four  per  cent  milk  and  20  per  cent  cream  is  intended 
for  each  formula  in  the  following  table : 

1  oz.  equals  2  standard  tablespoonfuls. 

1  drm.  equals  one  tablespoonful. 
30  gr.  equals  I  teaspoonful. 
20  gr.  equals  ^  teaspoonful. 

TABLE  FOR  PREPARING  FOOD  FOR  INFANTS 


Age  of  Infant 


First  week 

2d  to  6th  week  .  . 
6th  wk.  to  2d  mo, 

3d  to  6th  mo 

6th  to  7th  mo.  .  .  . 

8th  to  9th  mo 

10th  to  14th  mo.  . 


Cream 

Whey 

Water 

Milk 

2  drm. 

3  drm. 

3  drm. 

2  drm. 

1  oz. 

h  oz. 

^  oz. 

1  oz. 

1  oz. 

i  oz. 

1  oz. 

2^  oz. 

h  oz. 

2  oz. 

3^  oz. 

h  oz. 

li  oz. 

6  oz. 

h  oz. 

U  oz. 

7i  oz. 

Milk 

sugar 

20  gr. 
20  gr. 
30  gr. 
1  drm. 
1  drm. 
1  drm. 
1  drm. 


Both  lime  and  barley  water  are  frequently  substi- 
tuted for  a  part  or  all  of  the  water,  depending  on  the 
patient.  They  aid  in  separating  the  curd  of  milk  but 
are  somewhat  constipating.  The  greater  the  per  cent 
of  cream  in  milk  the  less  constipating,  and  vice  versa. 


THE  STANDARDIZATION  OF  MILK  97 

Prepare  mixtures  of  the  above  feeds  by  each  of  the 
formulas. 

Example  1 :  Prepare  a  feed  for  infant  four  months 
old  that  is  constipated,  otherwise  normal:  2 J  oz. 
4  per  cent  milk,  1  oz.  plain  or  oatmeal  water,  1  oz. 
20  per  cent  cream,  1  dram  milk  sugar. 

Example  2 :  Prepare  a  feed  for  infant  four  months 
old  that  has  diarrhoea,  otherwise  normal:  2J  oz.  4  per 
cent  milk,  1  oz.  barley  or  Hme  water,  0  to  J  oz.  20 
per  cent  cream,  1  dram  milk  sugar. 

Similarly  prepare  feeds  for  infants  of  various  ages. 

The  cream  for  infants  should  be  gravity  raised 
rather  than  separator  cream,  as  the  latter  has  a  ten- 
dency to  destroy  the  natural  emulsion  of  milk  and 
cream,  rendering  it  less  digestible  for  deUcate  infants 
or  invaUds. 

EXERCISE  XXV 
The  Standardization  of  Milk 

The  standardization  of  milk  consists  of  bringing 
the  butter  fat  content  to  a  certain  standard  or  per 
cent  regardless  of  the  quality  of  milk  produced. 

Example  1 :  Take  10  pounds  of  milk  testing  4.5  per 
cent  fat,  and  standardize  to  4  per  cent.  10  pounds 
milk  testing  4.5  per  cent  =  .45  pound  butter  fat. 

.45  -f-  .04      =  11.25  =    number  of  pounds  of  4  per 

cent  milk  required. 
11.25—10       =    1.25=    number  of  pounds  of  skim- 
milk  to  be  added. 


98  DAIRY  LABORATORY  GUIDE 

Example  2:  10  pounds  of  milk  containing  3  per 
cent  fat  is  to  be  standardized  to  4  per  cent.  How 
much  skim-milk  must  be  taken  from  the  whole 
milk? 

10  X    .03  =    .30  number  of  pounds  of  fat  in  original 

milk. 
.30  ^    .04  =  7.5    number  of  pounds  of  standardized 

milk. 
10  —  7.5    =    2.5  number  of  pounds  skim-milk  to  be 

separated  from  the  original  milk. 

The  table  on  the  opposite  page  by  Professor  Erf 
indicates  the  quantity  of  skim-milk  to  be  added  to  or 
subtracted  from  100  pounds  of  milk  to  make  a  de- 
sired per  cent. 

To  find  the  pounds  of  skim-milk  to  be  added  or 
removed,  trace  the  vertical  colunm  of  the  per  cent 
of  fat  desired  down  to  where  the  horizontal  column 
representing  the  per  cent  of  fat  in  the  milk  on  hand 
intersects,  and  the  result  will  be  the  number  of 
pounds  of  skim-milk  to  be  added  or  removed,  as 
indicated  by  a  plus  or  minus  sign  before  the  re- 
sult. 

To  illustrate:  If  milk  containing  4.5  per  cent  is 
desired  and  milk  containing  3.8  per  cent  is  on  hand, 
then  15.5  pounds  for  every  hundred  pounds  or  15.5 
per  cent  of  the  quantity  must  be  separated  out  as 
skim-milk. 


THE  STANDARDIZATION  OF  MILK 


99 


o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

O 

o 

o 

o 

O 

o 

88 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o  o 

iC 

d 

00 

d 

Tt^ 

(N 

d 

00 

d 

Tj5 

oi 

d 

00 

d 

Tt5 

(N 

d 

00 

d 

■<^ 

(N  d 

1 

CO 

1 

CO 

1 

CO 

1 

CO 

1 

CO 

1 

1 

1 

1 

1 

CN 

1 

1—1 

1 

7 

t—t 
1 

T— 1 
1 

7 

1 

1 

1 

1    1 

(M 

1> 

(N 

I> 

(N 

i> 

(N 

!> 

~ 

t^ 

(N 

t^ 

(N 

l> 

l> 

t^ 

(N 

i> 

t^ 

(N    l> 

^ 

CO 

CO 

(N 

(M 

1—1 

O 

§ 

05 

a> 

00 

00 

l^ 

(M 

CO 

CD 

to 

to 

CO   CD 

J2 

t-: 

CO 

lO 

(M 

CO 

<N 

00 

i> 

CD 

to 

Tt< 

CO 

c^< 

q 

q 

^   (N 

l> 

CD 

Ttl 

(N 

d 

00 

d 

^ 

d 

d 

t^ 

to 

CO 

^ 

d 

t>^ 

to 

CO 

1-H 

^ 

CO   to 

■^ 

CO 
1 

CO 

1 

CO 

■1 

CO 

1 

1 

1 

1 

i 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

+ 

+    + 

CO 

~ 

~ 

~ 

Ttl 

(M 

~ 

l^ 

lO 

CO 

~ 

"oo" 

"co" 

^ 

<M 

~ 

(M 

"^ 

"o" 

00     T-H 

CO 

r-i 

00 

CO 

■^ 

(M 

o 

t- 

iO 

CO 

r-H 

00 

CO 

^ 

(N 

o 

04 

rjH 

CO 

00    1—1 

S 

CO 

»-H 

00 

CO 

■^ 

(N 

o 

t>; 

»o 

CO 

1— I 

00 

CO 

■^ 

(N 

o 

(M 

"^ 

CD 

00  I— 1 

>o 

CO 

^ 

00 

d 

Tj^ 

(N 

d 

t^ 

lO 

CO 

r-H 

00 

d 

rt^ 

(N 

d 

(N 

-^ 

to 

00  -i 

T}5 

CO 

CO 

(M 

(N 

(M 

(M 

(N 

1— 1 

I— 1 

1—1 

1—1 

tH 

1 

1 

1 

1 

1 

1 

i 

1 

1 

1 

1 

1 

1 

1 

1 

1 

+ 

+    +    +    + 

(N 

o 

CO 

CO 

~ 

1> 

■* 

~ 

00 

to 

C<1 

05 

CO 

CD 

05 

~ 

to 

00 

1—1 

l>  o 

lO 

o 

»o 

(3 

Tfi 

Oi 

Tt^ 

00 

CO 

00 

(M 

r- 

t^ 

C^> 

00 

CO 

00 

Tfl 

CO  o 

;5 

"^ 

q 

t-: 

CO 

o 

CO 

(M 

Oi 

lO 

(M 

00 

■^ 

o 

O 

Tjl 

00 

(N 

to 

05 

c^ 

oi 

t^ 

-^ 

c^ 

d 

t^ 

lO 

(N 

d 

00 

to 

(N 

d 

d 

(N 

to 

00 

d 

(N 

i>  d 

Tj^ 

CN 

(N 

(N 

(M 

(N 

T— 1 

^    (N 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

+  +  +  +  + 

+ 

+    + 

o 

O 

"^ 

o 

O 

o 

O 

O 

8 

o 

o 

O 

o 

o 

O 

o 

o 

o 

O 

si 

o 

o 

»o 

o 

lO 

o 

lO 

o 

lO 

»o 

o 

to 

o 

to 

c 

to 

q 

to 

O 

Tj^ 

»o 

d 

d 

t^ 

lO 

d 

d 

t^ 

to 

d 

d 

(N 

to 

t^ 

d 

oi 

to 

t> 

d 

d    to 

1 

1 

1 

7 

1 

1 

7 

1 

1 

1 

1 

+ 

+ 

+ 

7 

+ 

1—1 
+ 

7 

+ 

+    + 

^ 

CO 

CO 

~ 

CO 

CD 

_ 

CO 

CO 

'o 

CO 

CO 

~ 

CO 

CO 

~ 

CO 

CO 

~ 

CO    CO 

^ 

CO 

CO 

Q 

CO 

CO 

Q 

CO 

CO 

CO 

CO 

Q 

CO 

CO 

Q 

CO 

CO 

3 

CD    CO 

lO 

o 

CO 

CO 

o 

CO 

CO 

o 

CO 

CO 

o 

CO 

CO 

o 

CO 

CO 

o 

q 

CO 

o 

CO    CO 

t^ 

d 

l> 

■^ 

(N 

d 

d 

■^ 

^ 

^ 

■^ 

d 

d 

d 

TJH 

t^ 

d 

(N 

to 

00 

^U 

CO 

<N 

r-l 

»— 1 

1—1 

c^ 

(N 

(M 

c^ 

1 

1 

1 

1 

1 

1 

1 

1 

+ 

+ 

+  + 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+    + 

lO 

CO 

1—1 

■^ 

1^ 

"^ 

i> 

■^ 

~ 

oo 

to 

CI 

~ 

"co" 

CO 

t>. 

't' 

~ 

00    to 

CO 

(N 

b- 

lO 

to 

t^ 

(M 

00 

'rp 

Oi 

to 

t^ 

(N 

00 

■^ 

gs 

S 

(N 

-^ 

lO 

t^ 

00 

o 

00 

t^ 

to 

•^ 

(>) 

Oi 

00 

t^ 

to 

^. 

<M 

lO 

Tt^ 

^ 

00 

lO 

(N 

d 

ci 

i6 

00 

,J^ 

Tj5 

I> 

d 

(N 

to 

00 

1—1 

'^ 

t-^ 

d  (N 

CO 

1-H 

1— ( 

1—1 

T— 1 

(M 

(N 

(N 

CO 

CO 

CO 

CO    Tt^ 

1 

1 

1 

1 

1 

1 

+  +  + 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+  + 

CO 

CO 

05 

05 

CO 

CO 

o 

!>• 

■^ 

^~ 

00 

to 

(M 

~ 

CO 

CO 

~ 

h- 

7 

^    X 

05 

CO 

CO 

Oi 

CO 

S8 

C5 

CD 

•^ 

(M 

05 

r>- 

to 

CO 

O 

CO    CO 

lO 

ys 

s 

lO 

iC 

CO 

CD 

t^ 

05 

05 

o 

1—1 

C^ 

C^ 

co 

Tfl 

to 

q 

CD 

t^    00 

(N 

l> 

'^ 

^ 

^ 

■^ 

t> 

d 

CO 

d 

oi 

CO 

d 

d 

<N 

to 

00 

^ 

■^ 

t>^ 

d  CO 

CO 

T-t 

T— 1 

(N 

(N 

(N 

CO 

CO 

CO 

Tt< 

"^ 

TfH 

to   to 

1 

I 

1 

++++++++++ 

+  4- 

++++++ 

< 

r^    ^ 

(N 

CO 

-^ 

kO 

CO 

t^ 

00 

OS 

o 

1-H 

(N 

co 

Tt< 

^. 

CD 

i> 

00 

05    O 

W    CO 

CO 

CO 

CO 

CO 

CO 

CO 

CO 

CO 

CO 

"^ 

Tji 

■^ 

-^ 

Tt^ 

■^ 

Tli 

Tli 

■Tji 

rji  to 

++ 

100  DAIRY  LABORATORY  GUIDE 

Standardizing  with  Whole  Milk 

Example  1:  20  pounds  of  milk  containing  3  per 
cent  fat  is  to  be  standardized  to  4  per  cent  fat  with 
5.2  per  cent  milk. 

.04    -  .03    =      .01 
.052  -  .04    =      .012 
.01     -  .012  =      .833 

20  X  .833  =  16.66,  number  of  pounds  of  5.2  per  cent 
milk  to  be  used. 

Example  2:  20  pounds  of  milk  containing  5.2  per 
cent  butter  fat  is  to  be  standardized  to  4  per  cent 
with  milk  containing  3  per  cent  butter  fat. 

.052  -    .04  =    .012 
.04    -    .03  =    .01 
.012  -    .01  =  1.2 

20  X  1.2  =  24,  number  of  pounds  of  3  per  cent  milk 
to  be  added  to  the  20  pounds  of  milk  to  decrease 
per  cent  fat  to  4  per  cent. 

The  same  principle  will  apply  in  standardizing  of 
cream. 

EXERCISE  XXVI 

Condensing  Milk 

1.  Attach  rubber  tubing  to  Bunsen  pump  and 
connect  to  a  strong  rounded,  quart  flask  containing 
about  a  pint  of  perfectly  sweet  milk  which  is  free 
from  all  taints.  Also  connect  to  a  graduated  glass 
tube  inserted  in  mercury  to  designate  the  amount  of 
vacuum  produced,  which  should  be  about  756  mm. 


CONDENSING  MILK 


101 


or  30  inches.  Tie  rubber  and  glass  connections  se- 
curely. Heat  milk  over  flame  at  130°  F.  and  allow 
to  boil  for  from  six  to  eight  hours  until  the  milk  has  a 
consistency  of  very  thick  cream.     Examine  and  taste. 


Fig.  47.  —  Condensing  Milk.  (6)  block  of 
wood;  (m)  mercury  in  bottle;  (c)  gradu- 
ated cylinder;  (s)  suction  from  Bunsen 
pump;  (0  thermometer;  (^)  lamp  or  Bun- 
sen  burner. 


2.  Condense  milk  as  above,  but  allow  to  remain  at 
90°  F.  instead  of  boiling-point  during  several  labo- 
ratory periods  until  it  has  entirely  dried.  Pulverize 
with  mortar  and  pestle  and  examine. 

3.  Take  10  pounds  of  curd  from  the  cheese  vat. 
After  removing  fat  evaporate  to  dryness  in  incubator 
or  oven.  Pulverize  and  feed  a  small  portion  to 
chickens.  Take  one  ounce  of  the  remaining  portion 
and  boil  together  with  5  c.c.  water.  When  an  emul- 
sion is  formed  boil  to  a  pasty  consistency  and  test 
the  sticking  quahties  for  glue. 


102  DAIRY   LABORATORY   GUIDE 

Milk  Paste 
Thoroughly  mix  three  parts  of  casein  with  one  part 
of  sodium  borate  (borax),  moisten  with  water  and 
test  for  paste.  This  is  frequently  used  for  library 
paste.  Mix  one  part  of  casein  with  one  part  of  quick 
lime,  moisten  and  test  for  glue. 

Dried  Milk 

Heat  15  pounds  of  skim-milk  in  vacuum  at  165°  F. 
until  it  dries  to  a  paste.  Frequently  turn  until  it 
forms  a  crisp  and  then  pulverize. 

Milk  Sugar 

Rapidly  coagulate  skim-milk  by  means  of  rennet 
or  acetic  acid.  Filter  whey  and  render  sHghtly 
alkaline  by  the  addition  of  lime  water.  Evaporate  to 
about  one-half  bulk  and  precipitate  albumen  by 
boiling  or  with  small  amount  of  alum.  Remove 
by  again  filtering  and  evaporate  the  second  time  to 
about  one-sixth  of  its  bulk.  Add  equal  volume  of 
methyl  alcohol,  and  allow  to  stand  for  three  to  six 
hours.  A  pure  white,  finely  crystalline  precipitate 
of  lactose  is  thrown  down  which  is  removed  by  filter. 
Cool  and  taste. 

EXERCISE  XXVII 

Junket 

To  1  small  junket  tablet  add  1  dram  (1  teaspoon- 
ful)  of  cold  water.     Crush  tablet  and  dissolve  thor- 


JUNKET  103 


oughly.  Heat  1  quart  of  pure  milk  to  about  90° 
to  98°  F.  and  add  sugar  and  flavor  to  suit  taste. 
Add  the  dissolved  tablet  to  the  milk,  mix  thoroughly, 
pour  into  desired  dishes  and  allow  to  stand  at  90°  to 
95°  F.  until  solidified.  Then  place  in  refrigerator 
until  ready  to  serve. 

If  no  junket  tablets  are  readily  obtainable  substi- 
tute a  mixture  of  ten  drops  of  rennet  and  a  few  grains 
of  salt. 

Papanized  Cheese  Paste 

This  process  is  patented 

Moisten  any  of  the  breakfast  food  cereals  and  put 
in  a  digester.  Heat  under  pressure,  not  exceeding 
three  atmospheres,  to  a  temperature  not  exceeding 
134°  C,  but  preferably  at  a  pressure  of  two  atmos- 
pheres and  a  temperature  of  121°  C.  for  an  hour  or 
more,  depending  on  the  amount  of  dextrinization 
desired.  Under  the  influence  of  the  moisture  and 
high  temperature  the  starch  in  the  cereals  becomes 
converted  into  dextrine.  Cut  cheese  into  small  bits 
and  crush  into  a  paste  with  equal  quantity  of  whole  or 
skim-milk.  One  to  one-half  per  cent  of  soda  may  be 
used  and  the  entire  mixture  cooked  to  the  desired 
taste  over  Bunsen  flame  until  the  cheese  is  com- 
pletely dissolved.  An  egg  may  also  be  added  if  ob- 
tainable. 


104  DAIRY  LABORATORY  GUIDE 

EXERCISE  XXVIII 
Atimidcaseose 

Process  patented 

Render  skim-milk  slightly  alkaline  with  lime-water 
or  sodium  carbonate  (NajCOa)  and  heat  to  4°  C. 
Add  just  sufficient  rennet  to  coagulate  and  filter  out 
whey.  Wash  curd.  Place  in  autoclave  if  obtainable 
and  subject  to  superheated  steam  at  a  pressure  of 
100  pounds  per  square  inch,  for  three  hours.  Curd 
thus  prepared  is  very  nutritious  and  readily  assimi- 
lated by  invalids.  Repeat,  using  5  pounds  of  whole 
milk  and  coagulate  as  rapidly  as  possible  by  means 
of  rennet.  Neutralize  by  baking  soda  and  filter. 
Taste  filtrate,  which  is  said  to  be  very  digestible  and 
which  is  often  used  for  invalids. 

Milk  Shake 
To  J  pint  of  whole  or  skim-milk  add  about  one  table- 
spoonful  of  sugar,  about  twice  that  amount  of  pow- 
dered ice,  a  pinch  of  baking  soda,  and  a  few  drops  of 
flavoring.     Shake  well  in  lemonade  shaker  and  serve. 

Buttermilk  Highball 

Mix  J  pint  of  buttermilk,  |  pint  of  ice  cream,  and 
a  pinch  of  baking  soda,  or  an  infusion  of  carbonic 
acid  gas  (CO2).  Shake  thoroughly  in  lemonade 
shaker  and  drink. 


KOUMISS  105 

Buttermilk  Pop 

To  }  gallon  of  fresh  buttermilk  add  I  pint  of 
20  per  cent  cream  and  }  pound  of  sugar,  also  a  few 
granules  of  salt.  Heat  to  boiling,  stirring  constantly 
to  keep  curd  well  mixed.  Add  8  grams  of  corn- 
starch previously  mixed  with  cold  water. 

Repeat  experiment,  using  J  pound  of  corn  meal  in 
place  of  corn-starch.  Add  a  pinch  of  baking  soda; 
shake  well  and  drink. 

Koumiss 

To  7  pints  of  pasteurized  milk,  either  skimmed 
or  3  per  cent,  add  4  ounces  of  cane  sugar  and  J 
cake  of  bakers'  yeast  after  pulverizing  and  dissolving 
in  about  3  ounces  of  lukewarm  water.  Mix  thor- 
oughly at  95°  F.  and  pour  into  a  long-necked  quart 
bottle.  A  champagne  bottle  answers  the  purpose 
very  well.  Fasten  a  light  wire  over  cork  to  prevent 
the  escape  of  air.  Allow  to  cool  gradually  and 
remain  at  60°  F.  to  70°  F.  for  twenty-four  to  thirty- 
six  hours.  Then  it  is  ready  for  use.  If  desired  to 
keep  longer  put  on  ice.  A  koumiss  faucet  inserted 
in  the  cork  before  allowing  to  ferment  greatly  facili- 
tates opening  the  bottle  for  use.  The  acid  developed 
in  koumiss,  like  that  of  buttermilk,  has  a  high 
dietetic  value,  is  readily  digested,  and  very  nutritious. 

Buttermilk 

Make  buttermilk  by  ripening  skim-milk  with  starter 
at  70°  F.   until  it  is  sHghtly  coagulated  but  has 


106  DAIRY  LABORATORY  GUIDE 

liberated  no  whey.  Add  about  30  per  cent  of  good 
flavored  buttermilk  and  churn  at  50°  to  55°  F.  until 
the  curd  is  entirely  emulsified,  when  it  is  ready  for 
use.  Repeat,  using  whole  milk  instead  of  skim-milk 
and  omit  the  addition  of  buttermilk. 

Drink  tw^o  glasses  of  buttermilk  daily  for  a  week 
and  note  effect  on  digestion. 

Buttermilk  contains  about  the  proper  amount  of 
lactic  acid  necessary  to  produce  perfect  digestion. 
It  is  anti-scorbutic  and  forms  carbonic  acid  in  the 
stomach,  which  unites  with  the  calcium,  magnesium, 
or  potassium  salts  that  are  always  present  in  the 
food,  and  forms  carbonates  which  purify  the  blood  by 
preserving  its  alkalinity;  while  alkaline  in  reaction 
the  blood  throws  off  uric  and  other  waste  acids  which 
would  otherwise  be  absorbed.  It  has,  therefore,  a 
great  diuretic  and  dietetic  value.  The  casein  is  in  a 
coagulated,  finely  divided  flocculent  state,  and  is 
readily  converted  into  peptones  for  body  use.  It 
contains  enough  water  to  quench  the  thirst,  takes  the 
place  of  fresh  fruit  to  a  great  extent,  keeps  the  body 
in  a  laxative  condition,  and  at  the  same  time  furnishes 
considerable  valuable  readily  digestible  food. 

Moose 

Make  what  is  known  as  Moose  by  adding  to  15  per 
cent  cream  about  20  per  cent  of  sugar  and  flavoring 
to  suit  the  taste.  Put  in  a  small  baking  powder  can 
or  small  ice  cream  packer  and  set  in  pulverized  ice 
to  which  a  small  amount  of  salt  has  been  added. 
Allow  to  freeze  without  stirring. 


PREPARATIONS  MADE  FROM  MILK  107 

Dried  Milk  Cocktail 

Take  a  given  quantity  of  skim-milk  and  add  one 
per  cent  of  grain  alcohol  until  precipitation  of  casein 
has  ceased.  Filter  the  precipitated  casein  from  the 
liquid.  Dry  at  from  145°  to  149°  F.  Above  this 
temperature  the  albumen  may  become  insoluble. 
Pulverize  and  mix  with  water,  milk,  beef-tea,  cocoa, 
or  hot  water  in  proportion  about  half  and  half,  or  to 
suit  the  taste.  Where  casein  has  thus  been  precipi- 
tated with  alcohol  and  then  dried  and  redissolved  in 
water  it  can  no  longer  be  curdled  by  pepsin  in  the 
stomach.  It  is  converted  from  insoluble  to  a  soluble 
form  without  losing  any  of  its  food  value. 

EXERCISE    XXIX 

(This  exercise  may  be  taken  or  omitted  at  the  option  of  the  in- 
structor.) 

Preparations  made  from  Milk 

Make  plasmon  or  caseon  by  precipitating  casein 
with  HCl,  neutrahze  with  carbonate  of  soda. 

Make  casein  of  lime  by  precipitating  casein  and  dis- 
solve by  phosphoric  acid  equal  to  quantity  of  lime  used. 

Make  nutrose  by  boiling  together  in  any  alkali 
solution  dried  casein  and  caustic  acid. 

Make  Santogene  by  mixing  95  per  cent  glycero- 
phosphate of  sodium  and  5  per  cent  casein.  Precip- 
itate casein  with  acetic  acid,  wash  with  methyl 
alcohol  and  dry  slowly. 

Make  eucasine  or  ammoniacal  casein  by  passing 
ammonia  through  the  enmlsion  of  alkaline  casein. 


108  DAIRY  LABORATORY  GUIDE 

Make  eulactol  by  dissolving  proteic  vegetable  sub- 
stance and  adding  hydrates  of  carbon,  salts,  such  as 
phosphate  of  calcium,  cooking  salt,  or  carbonate  of 
sodium,  and  allow  to  vaporize. 

Obtain  albumine  ^'nikol"  from  sterilized  whey  and 
dissolve  precipitate  in  soda  and  render  soluble  by 
treating  successively  with  HCl  and  alkali. 

Mix  albumine  ''nikol"  with  oxblood  10  to  2. 
This  mixture  is  a  hygiene  albumen  frequently  used 
by  people  suffering  from  chlorosis. 


EXERCISE  XXX 

Solid  Milk 

Prepare  solid  milk  by  adding  to  any  desirable 
quantity  of  whole  or  skim  milk  1  per  cent  of  liquid 
gelatine.  Put  up  in  any  desired  form,  and  allow  to 
soHdify  at  30  to  50°  F. 

Soap 

Boil  1  pound  of  milk  with  any  alkali  and  note 
difference  in  per  cent  of  fat  before  and  after  adding. 
12.5  per  cent  of  glycerine  unites  with  87.5  per  cent 
of  fatty  acid  to  form  fats.  When  fat  is  boiled  with 
alkali  the  latter  takes  the  place  of  glycerine  and 
forms  soap.  When  boiled  again  with  an  acid  the 
fat  returns  to  its  original  condition. 


DISINFECTANTS  109 

Preparation  for  Ivy  Poison 

Mix  1  pound  of  buttermilk  with  2  ounces  of  salt 
or  all  that  will  dissolve.  Apply  to  parts  of  skin 
affected  by  poison  ivy  or  similar  skin  diseases. 

A  Method  for  Modifying  Milk  for  Invalids 

Heat  a  given  quantity  of  milk  to  86°  F.  Add 
sufficient  rennet  to  coagulate  in  twenty  minutes  and 
mix  thoroughly.  After  precipitating  the  casein,  filter 
out  whey  and  modify  with  proper  per  cent  of  casein 
thus  obtained  to  give  the  percentage  of  protein 
(1.5  per  cent)  of  human  milk. 

Preserving  Casein 

Precipitate  casein  of  milk  by  use  of  sulphuric  or 
hydrochloric  acid  with  which  a  small  percentage  of 
borax  or  other  preservative  has  been  added  in  pro- 
portion of  i  to  1  per  cent  of  the  preservative.  Dry 
and  pulverize.  Thus  preserved  the  casein  is  unfit 
for  food,  but  may  be  used  in  the  manufacture  of  glue 
and  paint. 

EXERCISE  XXXI 

Disinfectants 

Prepare  the  following  disinfectants:  Solution  of 
corrosive  sublimate  (HgClj)  1  to  1000;  carbolic  acid, 
CeHsOH,  1  to  20;  formaldehyde  (HCHO  +  H^O)  1  to 
20.  Apply  to  infected  places  and  note  results.  Po- 
tassium permanganate  (KMn04)  1  to  20,  cold  water; 


110  DAIRY  LABORATORY  GUIDE 

Wyandotte  Dairyman's  Cleaner  and  Cleanser  1  to 
20;  Banner  Purifying  Compound  1  to  20;  borax  1 
to  20;  sal.  soda  1  to  20;  Fairbanks'  washing  powder 
1  to  20;  Tessico  washing  powder  1  to  20;  gold  dust 
1  to  20;  powdered  unslaked  lime  1  to  20;  powdered 
gypsum  1  to  20.  Use  and  note  results.  Gypsum  is 
preferable  to  lime  in  barns  or  on  any  material  which 
may  afterwards  be  used  for  fertilizer,  for  the  latter 
forms  soluble  salts  with  the  nitrogen  of  manure  and 
liberates  a  large  per  cent  of  the  ammonia  present. 
(NHJ^COs  +  CaO  =  2NH3  +  CaCOs  +  H^O. 
(NHJ^SO,  +  CaO  =  2NH3  +  CaSO^  +  H^O.  This 
causes  a  loss  of  valuable  fertilizer  and  produces  an 
offensive  odor  which  milk  readily  absorbs.  Gypsum, 
on  the  other  hand  (CaS04),  is  insoluble  with  the 
nitrogen  of  manure  and  is  retained  until  deposited 
in  the  fields. 

EXERCISE  XXXII 

Mechanical  Refrigeration 

If  refrigerating  machinery  is  in  use  at  the  college, 
note  the  kind  of  machine,  whether  vacuum,  absorp- 
tion, compression,  or  combined  absorption  and  com- 
pression. Note  principle  of  refrigeration  which  is 
the  production  of  cold  air  by  the  evaporation  of  liquids 
which  absorb  the  heat  in  vaporizing.  Anhydrous 
ammonia  is  generally  used  on  account  of  its  low 
boiling  point.  It  liquifies  at  30°  F.  under  one  atmos- 
pheric pressure.  It  hquifies  at  higher  temperatures 
by  subjecting  it  to  pressure.     It  is  alternately  evap- 


MECHANICAL  REFRIGERATION 


111 


112  DAIRY  LABORATORY  GUIDE 

orated  and  liquified  so  that  its  use  is  continuous. 
The  cycle  of  its  operation  starts  from  the  liquid 
receiver  and  enters  the  refrigerating  coils  in  which  it 
evaporates,  absorbing  a  large  amount  of  heat.  By 
means  of  a  compression  pump  operated  by  an  engine 
the  ammonia  vapors  are  forced  in  the  condenser  coils 
where  the  ammonia  under  pressure  is  again  liquified 
by  running  cold  water  over  the  coils.  Here  it  again 
enters  the  liquid  receiver  and  repeats  the  cycle.  The 
amount  of  refrigeration  is  regulated  by  an  expansion 
valve  placed  between  the  liquid  receiver  and  the 
refrigerating  coils.  This  valve  may  be  adjusted  so 
as  to  admit  the  condensed  quantity  of  liquid  ammonia 
to  the  coils.  Note  difference  between  brine  system 
and  direct  refrigeration.  Take  temperatures  of  brine. 
At  different  regulations  of  the  expansion  valve,  take 
temperature  of  the  room  surrounding  the  brine  tank. 
If  the  direct  refrigeration  system  is  used  entirely,  take 
temperatures  similarly  as  above  directed.  Note  size 
of  compressor  refrigerating  pipes,  power  required, 
expense  of  operating,  etc.  After  careful  examination 
of  the  machine,  charge  it  and  operate  under  direction 
of  the  operating  engineer  as  described  by  H.  H. 
Kelley: 

''Discharge  air  with  special  valves  by  starting  the 
compressor  and  pumping  it  out  by  reversing  the 
operation  of  the  gas  cylinder  to  that  of  its  working 
order.  Charge  with  proper  amount  of  anhydrous 
ammonia  through  the  charging  valve  by  connecting 
the  ammonia  cylinder  with  suitable  pipe,  and  open 
the  valve.     Run  compressor  slowly  with  the  suction 


MECHANICAL  REFRIGERATION 


113 


(|j)     9did,klJo'iiooVQ     ■^aUld.Ji 


■S 


<^ 


'ijd.^l  JO  IIOO 


^ 


»<IW.KlJoi[00 


^ 


114  DAIRY  LABORATORY  GUIDE 

and  discharge  valves  wide  open  and  expansion  valve 
closed.  As  soon  as  one  cylinder  is  empty  replace 
with  another,  being  careful  to  close  the  charging 
valve  before  attempting  to  remove  the  empty  cylin- 
der; opening  it  when  the  fresh  cylinder  is  connected. 
From  60  to  75  per  cent  of  the  full  charge  is  sufficient 
to  start  with,  so  that  any  air  not  having  been  removed 
may  escape  with  as  little  loss  of  ammonia  as  possible. 
Add  a  small  amount  of  ammonia  each  day  until  full 
charge  has  been  introduced.  The  glass  gage  on  the 
ammonia  receiver  will  indicate  the  amount  of  am- 
monia present.  The  appearance  of  frost  on  the  pipe 
leading  to  the  coils  and  the  cooling  of  the  brine  or 
air  in  refrigerator  in  the  tank  will  indicate  that 
enough  ammonia  has  been  introduced  to  start  with. 
It  sometimes  requires  applications  of  heat  to  entirely 
empty  the  ammonia  cylinder.  One  part  of  water  will 
absorb  800  parts  of  ammonia  gas,  therefore  for  use  in 
case  of  accident  keep  a  vessel  of  water  handy.  After 
starting  compressor  at  the  proper  speed  and  adjusting 
regulating  valve,  note  temperature  of  delivery  pipe, 
and  if  there  is  a  tendency  to  heat  open  it  wide,  and 
vice  versa.  With  too  light  charge  of  ammonia  the 
delivery  pipe  will  become  heated.  The  refrigerating 
room  should  be  about  15  degrees  lower  than  the  brine 
being  used,  and  the  temperature  of  the  water  dis- 
charged from  the  ammonia  condenser  should  be  about 
15  degrees  lower  than  that  of  the  condenser.  By 
placing  the  ear  close  to  the  expansion  valve  the 
ammonia  can  be  heard  passing  through  it.  If  the 
sound  is  uniform  and  continuous   the   machine   is 


MECHANICAL  REFRIGERATION  115 

working  properly.  If  too  much  air  is  present  the 
sound  will  be  irregular.  Remove  air  in  the  same 
manner  as  when  charging  the  system.  The  presence 
of  oil  or  water  is  detected  by  shocks  occurring  in  the 
compressor  cyhnder.  Oil  is  removed  by  an  oil 
separator  placed  in  main  pipe  between  compressor 
and  condenser." 

The  compressor  sucks  the  gaseous  ammonia  into 
its  cyhnder,  compresses  it  and  sends  it  into  the 
condenser.  The  latter  thus  describes  a  continuous 
circuit.  The  same  ammonia  is  used  continually.  A 
five-ton  refrigerating  machine  requires  about  an  18 
horse-power  boiler. 

The  compressor,  the  most  essential  part,  is  a 
pumping  engine,  used  to  pump  the  ammonia  gas 
from  the  cooling  apparatus  and  compress  it  and 
force  it  through  the  condenser  at  a  pressure  of  from 
150  to  185  pounds  per  square  inch.     See  illustration. 

The  machinery  for  pasteurizing  and  clarifying  2500 
quarts  of  milk  and  for  a  refrigerating  machine  of 
five  tons,  will  cost  about  $2500. 

An  ice  plant  which  wull  make  two  and  one-half 
tons  of  ice  will  have  a  refrigerating  capacity  of  five 
tons;  that  is,  it  will  cool  as  much  as  will  five  tons 
of  ice  melting  in  twenty-four  hours. 

For  ice-making,  pasteurizing,  ice  cream  making 
and  running  a  separator,  not  less  than  a  30  horse- 
power boiler  should  be  used. 

The  water  used  in  the  condenser  is  warm  and  can 
be  stored  up  for  various  purposes. 

About  a  half  ton  of  coal  is  required  daily  to  make 


116  DAIRY  LABORATORY  GUIDE 

two  and  one-half  tons  of  ice  or  five  tons  of  refrigerating 
capacity.  It  requires  from  twelve  to  eighteen  hours 
to  cool  off  a  room  containing  1000  cubic  feet  and  to 
make  one  ton  of  ice,  depending  on  the  perfection  of 
the  insulation,  on  the  outside  temperature,  and  on 
the  contents  of  the  cold  storage  room. 

Ice  ordinarily  does  not  reduce  the  temperature 
below  40°  F.,  but  by  running  the  engine  continually 
the  temperature  can  be  reduced  as  low  as  desired, 
even  to  zero. 

A  two-story  plant:  The  brine  tank  can  be  placed 
right  above  the  cold-storage  room,  and  thus  keep  it 
cool  after  the  machinery  stops.  A  building  24  by 
30  feet  is  ample  for  a  dairy  of  2500  quarts  capacity. 

Direct-expansion  system  is  much  cheaper  than  the 
brine  system,  providing  ice  is  not  manufactured  for 
sale;  the  brine  tank,  brine  pump,  and  secondary 
system  of  pipes  for  brine  circulation  being  dispensed 
with,  and  also  a  greater  efficiency  is  obtained.  Only 
about  two-thirds  of  the  pipe  surface  is  required  to 
produce  the  same  effect.    See  illustration. 

A  Non-frosting  Gage  Glass 

A  device  to  prevent  frost  from  gathering  on  the 
glass  gage  is  described  by  R.  L.  Shipman.  The 
method  is  simply  to  jacket  the  ordinary  form  of 
gage  glass  with  another  glass  of  larger  diameter,  so 
that  there  will  be  an  annular  space  of  an  eighth  of 
an  inch  or  so  between  the  glasses.  Then  place  a  soft 
rubber  ring  between  the  glasses  at  each  end,  making 
air-tight  joints.    The  air  thus  enclosed  between  the 


CREAMERY  BOOKEEPING  117 

glasses  will  contain  such  a  small  quantity  of  moisture 
that  no  frost  will  appear  on  the  inner  glass,  and  this 
air  space  being  such  a  poor  conductor  the  outer  glass 
will  not  be  cooled  to  a  temperature  sufficiently  low 
to  produce  frost.  Although  a  considerable  amount 
of  moisture  may  be  condensed  on  its  outer  surface, 
this  will  not  interfere  in  any  way  with  a  clear  view 
of  the  liquid  contained  in  the  inner  glass.  This  com- 
bination has  been  used  with  temperatures  as  low  as 
30°  below  zero  F.,  and  no  frost  has  appeared  on  the 
outer  glass  to  obstruct  the  view. 

EXERCISE  XXXIII 

Creamery  Bookkeeping 

Either  single  or  double  entry  systems  may  be  used, 
but  the  single  entry  system  is  more  practical  for 
creamery  accounts;  for  it  eliminates  the  transfer  of 
entries  and  the  keeping  of  more  books.  The  single- 
entry  system  consists  of  a  day  book,  in  which  careful 
record  of  all  money  spent  for  repairs,  supplies,  etc., 
and  all  money  taken  in  from  sales  of  milk,  cream, 
butter,  ice-cream,  etc.,  credits  and  debits  are  kept; 
an  order  book,  sales  book,  cash  book,  and  ledger  to 
which  the  above  are  transferred  every  evening.  The 
milk  sheet,  test-book,  butter  slips,  patrons'  state- 
ments, etc.,  are  figured  at  the  end  of  each  month, 
or  according  to  the  custom  of  the  management.  The 
following  blank  has  been  used  for  several  years 
by  the  writer  and  proved  to  be  very  satisfactory: 


118  DAIRY  LABORATORY  GUIDE 

STATE  AGRICULTURAL  COLLEGE 

Dairy  Husbandry  Dept. 
Creamery  Patron's  Monthly  Statement 


190-. 


Mr 


No 


Date 
shipped 

Date 
received 

Pounds 

Test 

Butter 
fat 

Price 

Amount 

Charges 

Items 

Check 



-- 



— 



Tota 

Is   . 

- 



Check  herewith 


A  creamery  record  should  be  kept  by  every  butter- 
maker  in  order  to  trace  causes  of  difficulty  in  ripening 
cream,  or  in  churning,  and  also  to  aid  him  in  main- 
taining regularity  of  work  and  uniformity  of  product. 
The  following  blanks  by  Professor  Erf  may  be  used 
for  keeping  daily  records : 


CREAMERY  BOOKKEEPING 


119 


DAILY   REPORT   IN    BUTTER   MAKING 
Date:    From to 190. 


Weather    to-day:    Fair,    Cloudy, 

Stormy    

Temperature 

Milk,  1st  grade,  pounds 

1st  grade,  per  cent  of  fat  .  .  . 

1st  grade,  pounds  of  fat    ... 

2d  grade,  pounds 

2d  grade,  per  cent  of  fat  ... 

2d  grade,  pounds  of  fat  .... 

3d  grade,  pounds 

3d  grade,  per  cent  of  fat   ... 

3d  grade,  pounds  of  fat  .... 


Pounds  of  skim-milk 

Test  of  skim-milk    

Pounds  of  fat  in  skim-milk    ... 
Cream  received  from  patrons  .  . 

1st  grade,  pounds    

1st  grade,  per  cent  of  fat 
1st  grade,  pounds  of  fat. 

2d  grade,  pounds 

2d  grade,  per  cent  of  fat 
2d  grade,  pounds  of  fat  . 

3d  grade,  pounds 

3d  grade,  per  cent  of  fat 
3d  grade,  pounds  of  fat  . 
Pounds  of  rinse  water  added  to: 

1st  grade 

2d  grade    

3d  grade    

Acidity  l)efore  pasteurizing: 

1st  grade 

2d  grade 

3d  grade 


Mon.  Tues.   Wed  Thur 


Fri. 


Sat. 


120  DAIRY  LABORATORY  GUIDE 

GRADE  OF  CREAM   NO.   (  ) 


Temperature  pasteurized 

Temperature  cooled  to 

Acidity  after  pasteurizing    

Starter-pounds  or  per  cent  added 

Acidity  of  starter  when  used 

Cream-temperature  cream  ripened 

Pounds  cream  to  be  churned 

Test  of  cream  to  be  churned 

Pounds  butter  fat 

Per  cent  of  acidity  in  cream 

Temperature  of  cream    

How  long  held  at  this  temperature 

Time    between   pasteurizing   and 
churning 

Color  —  Ounces  or  c.c.  color  used 

Churning  —  How  full  was  churn 

Time  required  to  churn    

Temperature  of  butter 

Temperature  of  buttermilk    

Size  of  granules  (very  fine,  wheat, 
peas,  lumps) 

Shape  of  granules  (round,  ragged) 

Temperature  of  wash  water 

Number  of  times  washed 

Salt  —  Amount  salt  used 

Working  —  Working  time  or  revo- 
lutions   

Per  cent  fat  in  buttermilk 

Pounds  fat  lost  in  manufacturing 

Pounds  butter  made 

Per  cent  overrun 

Account  —  No.  packages  put  in 
refrigerator 

No.  packages  sold 

Refrigerator  temperature 

Butter-maker's  score 

Expert's  score 

Report  from  commission  man  . .  . 

Remarks : 


Mon.  Tues.  Wed.  Thur.  Fri.     Sat 


CREAMERY  BOOKKEEPING  121 

EXERCISE  XXXIV 
Writing  to  Patrons 

Prepare  a  letter  for  creamery  patrons  similar  to  the 
following,  with  variations  to  suit  the  circumstances. 

We  aim  to  put  out  the  highest  standard  of  dairy 
products  from  this  creamery.  In  order  to  do  this  it 
is  necessary  that  there  should  be  perfect  cleanliness 
in  all  of  our  operations.  We  wish  to  ask  all  who 
have  anything  to  do  with  milk  brought  here  to  co- 
operate with  us  in  bringing  about  the  best  results. 
We  desire  to  make  the  following  suggestions: 

1.  The  milk  haulers  must  keep  their  wagons  free 
from  dirt  and  filth. 

2.  The  cow  stables  should  be  kept  cleaned  and 
ventilated. 

3.  The  feeding  and  bedding  of  cows  must  be  done 
after  milking,  as  the  dust  contains  bacteria  that  will 
spoil  the  milk. 

4.  The  milkers  must  not  get  anything  in  the  pail 
from  the  cow's  udder  but  milk.  To  aid  in  this  matter 
a  damp  cloth  may  be  used  to  advantage  in  wiping  the 
cow's  udder  before  milking,  and  the  first  stream  from 
each  teat  discarded. 

5.  In  straining  the  milk  use  a  double  strainer 
covered  pail.  The  common  strainer  is  not  sufficient 
to  take  out  the  fine  particles  of  dirt.  Milk  should  be 
cooled  to  as  low  temperature  as  possible  inmiediately 
after  milking. 

6.  After  thoroughly  washing  all  pails,  pans, 
strainers,  cans,  etc.,  with  good  washing  powder,  they 


122  DAIRY  LABORATORY  GUIDE 

must  be  scalded  with  boiling  water  to  destroy  the 
harmful  germs. 

7.  The  skim-milk  should  never  be  left  standing  in 
the  cans.  It  is  best  to  empty  the  cans,  wash  them, 
and  scald  with  hot  water  or  steam. 

8.  Fresh  milk  should  be  cooled  before  mixing  with 
other  milk. 

EXERCISE    XXXV 

Creamery  Conveniences 

A  fan  in  the  creamery  keeps  the  air  cool,  fresh,  and 
the  flies  outside. 

A  low-water  whistle  alarm  on  the  boiler  as  required 
by  the  state  law  of  Michigan. 

A  cord  connected  to  the  safety  valve  on  the  boiler 
and  stapled  around  the  periphery  of  the  creamery, 
with  a  weight  attached  suflftcient  to  pull  the  valve 
open  if  the  cord  is  ever  burned  in  two.  In  case  of 
fire  the  steam  and  hot  water  will  aid  materially  in 
extinguishing  it. 

An  automatic  scale  to  show  the  weight  of  the  milk 
as  soon  as  emptied  into  the  weigh  can,  similar  to  a 
butcher's  scale,  with  agate  bearings. 

The  butter  printing  table  to  be  fastened  on  the 
wall,  with  hinges  and  drop  legs. 

Pipe  brushes  with  sectional  handles  to  clean  milk 
pipes. 

A  heater  regulator  to  control  the  temperature  of 
the  milk  when  separating;  also  cream  when  pas- 
teurizing. 


CREAMERY  CONVENIENCES  123 

Steam  and  water  connected  with  hose  to  wash 
vats,  walls,  and  floor.  Cases  for  separator  and  pas- 
teurizer parts  hung  neatly  on  the  wall  near  the 
machines  as  shown  in  Fig.  6. 

A  case  similar  to  the  above  for  a  complete  set  of 
creameryman's  tools. 

An  oilcloth  to  cover  the  engine  and  separators 
when  not  in  use,  to  keep  off  the  dust. 

A  clamp  to  hold  small  butter  tubs  and  5-pound 
boxes  firm  when  packing  them. 

A  home-made  water  pump  regulator  is  a  most 
helpful  and  economical  device.  It  is  made  by  at- 
taching a. float  on  the  water  tank  to  one  end  of 
a  lever,  the  other  end  of  which  is  attached  to 
the  throttle  of  the  pump  in  such  a  way  that  as  the 
water  in  the  tank  rises  or  falls  it  shuts  or  opens 
the  throttle.  This  not  only  keeps  the  tank  full  but 
the  pump  adjusts  itself  to  the  varying  boiler  pressure 
and  to  the  quantity  of  water  used.  The  water  is 
pumped  into  and  drawn  out  of  the  tank  through  a 
siphon,  so  that  as  soon  as  the  pump  starts  the  water 
comes  direct  from  the  spring  or  well. 

An  adjustable  overflow  on  the  water  jacket  of  the 
cream  vat,  made  by  screwing  in  a  short  piece  of  pipe 
and  elbow  on  the  inside  near  the  bottom,  with  a 
corresponding  rod  on  the  outside  to  indicate  its  posi- 
tion, and  a  vertical  pipe  in  the  elbow  which  can  be 
turned  up  or  down  to  keep  the  water  the  same 
height  as  cream.  This  enables  one  to  keep  a  continual 
stream  of  water  running  around  it  and  saves  ice  and 
time. 


124 


DAIRY  LABORATORY  GUIDE 


Elevator  for  carrying  boxes,  etc.,  to  attic. 
The  milk  can  elevator  invented  by  0.  B.  Schier, 
of  Baltimore,  consists  of  two  endless  chains  running 


1 

1.  ItfLfSBlm^ 

m 

\^^^ 

3 

ifl^ 

'"■   \.,v^'^"  '~" 

Fig.  50.  —  Milk  Can  Elevator.     Upper  Floor 

over  sprocket  wheels,  connected  by  a  single  shaft  at 
the  lower  end  in  such  a  way  that  both  chains  must 
travel  at  the  same  speed.  Between  the  chains  are 
suspended  on  swivel  links  a  number  of  swinging 


CREAMERY  CONVENIENCES 


125 


platforms  to  carry  the  cans  from  one  elevation  to 
another.  They  are  just  far  enough  apart  to  allow 
a  man  to  conveniently  put  on  the  milk  cans  as  fast 


Milk  Can  Eleviit 


Lower  Floor 


as  he  takes  them  from  the  wagon.  The  elevator 
delivers  the  cans  to  a  higher  elevation  or  higher 
floor  continuously  as  fast  as  would  be  possible  to 


126  DAIRY  LABORATORY  GUIDE 

unload  them;  while  in  the  regular  platform  ele- 
vators it  is  necessary  to  wait  until  the  elevator  is 
loaded.  Thus,  it  will  be  seen  that  the  endless  chain 
elevator  saves  a  great  deal  of  help. 

Test  bottle  rack  with  perforated  top,  for  shaking 
or  emptying  twenty-four  to  forty  bottles  at  the  same 
time. 

Automatic  governor  brake  to  stop  engine  in  case 
of  governor  belt  breaking  or  coming  off. 

Heater  for  warming  water  going  into  boiler;  the 
exhaust  from  engine  may  be  utilized  for  this  pur- 
pose. 

Weigh  can  gate  opener,  saves  stooping. 

Castors  on  movable  vats  and  creamery  appliances. 

Steam  gage  in  working  room  to  show  boiler 
pressure. 

Slatted  draining  shelves  for  all  creamery  appara- 
tus. 

Place  ice-box  above  the  refrigerator  with  a  sloping 
floor.  Connect  a  drain  at  the  lower  side  so  as  to 
run  the  water  into  a  small  pipe  leading  into  a  vat, 
which  is  arranged  with  slat  shelves  that  hold  one-half 
pint,  pint,  and  quart  bottles,  the  water  reaching  just 
to  the  neck  of  each.  Insert  an  overflow  pipe  and 
drain  the  water  from  this  into  another  vat  beneath, 
where  milk  and  cream  cans  may  be  placed.  The 
water  in  the  latter  vat  is  allowed  to  rise  to  within  an 
inch  of  the  top  of  the  can  before  it  reaches  the  over- 
flow. Thus,  after  the  ice  has  been  used  for  coohng 
the  refrigerator,  the  ice-water  may  be  utilized  twice 
for  coohng  purposes. 


CREAMERY   CONVENIENCES 


127 


An  electric  alarm  bell  attached  by  means  of  a  cord 
to  a  float  in  the  milk  vat.  As  the  milk  is  pumped  or 
drawn  from  the  vat  the  float  lowers  and  pulls  a 
metallic  weight  against  a  brake  which  causes  the  bell 
to  ring,  thus  notifying  the  operator  that  the  vat  is 
almost  empty. 

COMPOSITION  OF  NORMAL  CREAM 


Total  Solids 

Solids  Not  Fat 

Fat 

32.50% 

6.83% 

25.67% 

37.59% 

6.14% 

31.45% 

50.92% 

5.02% 

45.90% 

55.05% 

4.65% 

50.40% 

57.99% 

4.17% 

53.82% 

68.18%, 

3.30% 

64.88% 

Water 68.0% 

Fat    25.0% 

Sugar 4.0% 

Proteids    2.6% 

Ash    4% 


100.0% 

COMPOSITION   OF  WHOLE  MILK 

Water 87% 

Fat    4% 

Milk  Sugar 5% 

Proteids    3.3% 

Ash    7% 


COMPOSITION   OF  NORMAL   BUTTERMILK 

Water 90.39% 

Fat    40% 

Milk  sugar    3.66% 

Lactic  Acid    80% 

Proteids    4.0  % 

Ash   75% 


128  DAIRY  LABORATORY  GUIDE 


COMPOSITION   OF  NORMAL  SKIM-MILK 

Water 90.50% 

Fat    10% 

Milk  Sugar 4.95% 

Casein 3.15% 

Albumen 42% 

Ash   78% 


APPENDIX    TO    EXERCISE   XV 


129 


The  Hygrodeik 


With  this  instrument  the  Relative  Humidity  of  the  air  may  be 
determined  without  the  use  of  tables.     See  Exercise  XV. 

To  find  the  Relative  Humidity  swing  the  index  hand  to  the 
left  of  the  chart,  and  adjust  the  sliding  pointer  to  that  degree  of 
the  Wet  Bulb  Thermometer  Scale  at  which  the  mercury  stands. 
Then  swing  the  index  hand  to  the  right,  until  the  sliding  pointer 
intersects  the  curved  line  which  extends  downward  to  the  left 
from  the  degree  of  the  Dry  Bulb  Thermometer  Scale  at  which 
the  mercury  stands.  At  this  intersection  the  index  hand  will 
point  to  the  Relative  Humidity  on  the  scale  at  the  bottom  of 
the  chart. 

Example:  The  temperature  indicated  by  the  Wet  Bulb  Ther- 
mometer is  C0°,  and  that  of  the  Dry  Bulb  70°.  The  index  hand 
will  indicate  the  Relative  Humidity  55°  when  the  pointer  rests 
on  the  intersecting  lines  of  GO  and  70  degrees. 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BEIiOW 


AN  INITIAL  FINE  OF  25  CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  50  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.00  ON  THE  SEVENTH  DAY 
OVERDUE. 


LIBKAEY,  COLLEGE  OF  AGRICULTURE,  DAVIS 
UNIVERSITY  OF  CALIFORNIA 

5m-4,'41  (2361s) 


40843 

SF253 

Melick,  C.W 

• 

M4 

Dairy  lab 

oratory 

guide. 

X 

^^ 

//^^.  C.A/. 


^-3 


y^-f- 


/^^  f'^j 


LIBRARY,  COUjEGE  OF  AGRICULTURE,  DAVIS 
UNIVERSITY  OF  CALIFORNIA 


